--- a/chrome/nsChromeRegistry.cpp
+++ b/chrome/nsChromeRegistry.cpp
@@ -27,19 +27,17 @@
 #include "nsIWindowMediator.h"
 #include "nsIPrefService.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Printf.h"
 #include "mozilla/StyleSheet.h"
 #include "mozilla/StyleSheetInlines.h"
 #include "mozilla/dom/Location.h"
 
-#ifdef ENABLE_INTL_API
 #include "unicode/uloc.h"
-#endif
 
 nsChromeRegistry* nsChromeRegistry::gChromeRegistry;
 
 // DO NOT use namespace mozilla; it'll break due to a naming conflict between
 // mozilla::TextRange and a TextRange in OSX headers.
 using mozilla::StyleSheet;
 using mozilla::dom::IsChromeURI;
 using mozilla::dom::Location;
@@ -633,46 +631,23 @@ nsChromeRegistry::MustLoadURLRemotely(ns
     *aResult = !!(flags & REMOTE_REQUIRED);
   }
   return NS_OK;
 }
 
 bool
 nsChromeRegistry::GetDirectionForLocale(const nsACString& aLocale)
 {
-#ifdef ENABLE_INTL_API
   int pref = mozilla::Preferences::GetInt("intl.uidirection", -1);
   if (pref >= 0) {
     return (pref > 0);
   }
   nsAutoCString locale(aLocale);
   SanitizeForBCP47(locale);
   return uloc_isRightToLeft(locale.get());
-#else
-  // first check the intl.uidirection.<locale> preference, and if that is not
-  // set, check the same preference but with just the first two characters of
-  // the locale. If that isn't set, default to left-to-right.
-  nsAutoCString prefString = NS_LITERAL_CSTRING("intl.uidirection.") + aLocale;
-  nsCOMPtr<nsIPrefBranch> prefBranch (do_GetService(NS_PREFSERVICE_CONTRACTID));
-  if (!prefBranch) {
-    return false;
-  }
-
-  nsCString dir;
-  prefBranch->GetCharPref(prefString.get(), getter_Copies(dir));
-  if (dir.IsEmpty()) {
-    int32_t hyphen = prefString.FindChar('-');
-    if (hyphen >= 1) {
-      nsAutoCString shortPref(Substring(prefString, 0, hyphen));
-      prefBranch->GetCharPref(shortPref.get(), getter_Copies(dir));
-    }
-  }
-
-  return dir.EqualsLiteral("rtl");
-#endif
 }
 
 NS_IMETHODIMP_(bool)
 nsChromeRegistry::WrappersEnabled(nsIURI *aURI)
 {
   nsCOMPtr<nsIURL> chromeURL (do_QueryInterface(aURI));
   if (!chromeURL)
     return false;
@@ -710,33 +685,23 @@ nsChromeRegistry::GetSingleton()
     return nullptr;
 
   return cr.forget();
 }
 
 void
 nsChromeRegistry::SanitizeForBCP47(nsACString& aLocale)
 {
-#ifdef ENABLE_INTL_API
   // Currently, the only locale code we use that's not BCP47-conformant is
   // "ja-JP-mac" on OS X, but let's try to be more general than just
   // hard-coding that here.
   const int32_t LANG_TAG_CAPACITY = 128;
   char langTag[LANG_TAG_CAPACITY];
   nsAutoCString locale(aLocale);
   UErrorCode err = U_ZERO_ERROR;
   // This is a fail-safe method that will set langTag to "und" if it cannot
   // match any part of the input locale code.
   int32_t len = uloc_toLanguageTag(locale.get(), langTag, LANG_TAG_CAPACITY,
                                    false, &err);
   if (U_SUCCESS(err) && len > 0) {
     aLocale.Assign(langTag, len);
   }
-#else
-  // This is only really needed for Intl API purposes, AFAIK,
-  // so probably won't be used in a non-ENABLE_INTL_API build.
-  // But let's fix up the single anomalous code we actually ship,
-  // just in case:
-  if (aLocale.EqualsLiteral("ja-JP-mac")) {
-    aLocale.AssignLiteral("ja-JP");
-  }
-#endif
 }

--- a/devtools/client/debugger/test/mochitest/browser_dbg_search-basic-01.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_search-basic-01.js
@@ -29,19 +29,16 @@ function test() {
     performTest();
   });
 }
 
 function performTest() {
   // Make sure that the search box becomes focused when pressing ctrl+f - Bug 1211038
   gEditor.focus();
   synthesizeKeyFromKeyTag(gDebugger.document.getElementById("tokenSearchKey"));
-  let focusedEl = Services.focus.focusedElement;
-  focusedEl = focusedEl.ownerDocument.getBindingParent(focusedEl) || focusedEl;
-  is(focusedEl, gDebugger.document.getElementById("searchbox"), "Searchbox is focused");
 
   setText(gSearchBox, "#html");
 
   EventUtils.synthesizeKey("VK_RETURN", { shiftKey: true }, gDebugger);
   is(gFiltering.searchData.toSource(), '["#", ["", "html"]]',
     "The searchbox data wasn't parsed correctly.");
   ok(isCaretPos(gPanel, 35, 7),
     "The editor didn't jump to the correct line.");

--- a/devtools/client/sourceeditor/codemirror/README
+++ b/devtools/client/sourceeditor/codemirror/README
@@ -1,16 +1,16 @@
 This is the CodeMirror editor packaged for the Mozilla Project. CodeMirror
 is a JavaScript component that provides a code editor in the browser. When
 a mode is available for the language you are coding in, it will color your
 code, and optionally help with indentation.
 
 # Upgrade
 
-Currently used version is 5.29.0. To upgrade: download a new version of
+Currently used version is 5.30.0. To upgrade: download a new version of
 CodeMirror from the project's page [1] and replace all JavaScript and
 CSS files inside the codemirror directory [2].
 
 Then to recreate codemirror.bundle.js:
  > cd devtools/client/sourceeditor
  > npm install
  > webpack
 

--- a/devtools/client/sourceeditor/codemirror/addon/edit/closebrackets.js
+++ b/devtools/client/sourceeditor/codemirror/addon/edit/closebrackets.js
@@ -18,31 +18,36 @@
   var Pos = CodeMirror.Pos;
 
   CodeMirror.defineOption("autoCloseBrackets", false, function(cm, val, old) {
     if (old && old != CodeMirror.Init) {
       cm.removeKeyMap(keyMap);
       cm.state.closeBrackets = null;
     }
     if (val) {
+      ensureBound(getOption(val, "pairs"))
       cm.state.closeBrackets = val;
       cm.addKeyMap(keyMap);
     }
   });
 
   function getOption(conf, name) {
     if (name == "pairs" && typeof conf == "string") return conf;
     if (typeof conf == "object" && conf[name] != null) return conf[name];
     return defaults[name];
   }
 
-  var bind = defaults.pairs + "`";
   var keyMap = {Backspace: handleBackspace, Enter: handleEnter};
-  for (var i = 0; i < bind.length; i++)
-    keyMap["'" + bind.charAt(i) + "'"] = handler(bind.charAt(i));
+  function ensureBound(chars) {
+    for (var i = 0; i < chars.length; i++) {
+      var ch = chars.charAt(i), key = "'" + ch + "'"
+      if (!keyMap[key]) keyMap[key] = handler(ch)
+    }
+  }
+  ensureBound(defaults.pairs + "`")
 
   function handler(ch) {
     return function(cm) { return handleChar(cm, ch); };
   }
 
   function getConfig(cm) {
     var deflt = cm.state.closeBrackets;
     if (!deflt || deflt.override) return deflt;

--- a/devtools/client/sourceeditor/codemirror/addon/hint/show-hint.js
+++ b/devtools/client/sourceeditor/codemirror/addon/hint/show-hint.js
@@ -297,17 +297,17 @@
         if (completion.options.completeOnSingleClick) widget.pick();
       }
     });
 
     CodeMirror.on(hints, "mousedown", function() {
       setTimeout(function(){cm.focus();}, 20);
     });
 
-    CodeMirror.signal(data, "select", completions[0], hints.firstChild);
+    CodeMirror.signal(data, "select", completions[this.selectedHint], hints.childNodes[this.selectedHint]);
     return true;
   }
 
   Widget.prototype = {
     close: function() {
       if (this.completion.widget != this) return;
       this.completion.widget = null;
       this.hints.parentNode.removeChild(this.hints);

--- a/devtools/client/sourceeditor/codemirror/addon/search/search.js
+++ b/devtools/client/sourceeditor/codemirror/addon/search/search.js
@@ -127,16 +127,17 @@
       queryDialog = doc.createElement("div");
       queryDialog.appendChild(inp);
       queryDialog.style.display = "flex";
     }
 
     var state = getSearchState(cm);
     if (state.query) return findNext(cm, rev);
     var q = cm.getSelection() || state.lastQuery;
+    if (q instanceof RegExp && q.source == "x^") q = null
     if (persistent && cm.openDialog) {
       var hiding = null
       var searchNext = function(query, event) {
         CodeMirror.e_stop(event);
         if (!query) return;
         if (query != state.queryText) {
           startSearch(cm, state, query);
           state.posFrom = state.posTo = cm.getCursor();

--- a/devtools/client/sourceeditor/codemirror/addon/selection/mark-selection.js
+++ b/devtools/client/sourceeditor/codemirror/addon/selection/mark-selection.js
@@ -81,17 +81,17 @@
     if (cm.listSelections().length > 1) return reset(cm);
 
     var from = cm.getCursor("start"), to = cm.getCursor("end");
 
     var array = cm.state.markedSelection;
     if (!array.length) return coverRange(cm, from, to);
 
     var coverStart = array[0].find(), coverEnd = array[array.length - 1].find();
-    if (!coverStart || !coverEnd || to.line - from.line < CHUNK_SIZE ||
+    if (!coverStart || !coverEnd || to.line - from.line <= CHUNK_SIZE ||
         cmp(from, coverEnd.to) >= 0 || cmp(to, coverStart.from) <= 0)
       return reset(cm);
 
     while (cmp(from, coverStart.from) > 0) {
       array.shift().clear();
       coverStart = array[0].find();
     }
     if (cmp(from, coverStart.from) < 0) {

--- a/devtools/client/sourceeditor/codemirror/addon/tern/tern.js
+++ b/devtools/client/sourceeditor/codemirror/addon/tern/tern.js
@@ -566,17 +566,17 @@
       var indent = CodeMirror.countColumn(doc.getLine(endLine), null, tabSize);
       if (indent <= minIndent) break;
     }
     var from = Pos(minLine, 0);
 
     return {type: "part",
             name: data.name,
             offsetLines: from.line,
-            text: doc.getRange(from, Pos(endLine, 0))};
+            text: doc.getRange(from, Pos(endLine, end.line == endLine ? null : 0))};
   }
 
   // Generic utilities
 
   var cmpPos = CodeMirror.cmpPos;
 
   function elt(tagname, cls /*, ... elts*/) {
     var e = document.createElement(tagname);

--- a/devtools/client/sourceeditor/codemirror/codemirror.bundle.js
+++ b/devtools/client/sourceeditor/codemirror/codemirror.bundle.js
@@ -515,23 +515,28 @@ var CodeMirror =
 
 	// Returns a number from the range [`0`; `str.length`] unless `pos` is outside that range.
 	function skipExtendingChars(str, pos, dir) {
 	  while ((dir < 0 ? pos > 0 : pos < str.length) && isExtendingChar(str.charAt(pos))) { pos += dir }
 	  return pos
 	}
 
 	// Returns the value from the range [`from`; `to`] that satisfies
-	// `pred` and is closest to `from`. Assumes that at least `to` satisfies `pred`.
+	// `pred` and is closest to `from`. Assumes that at least `to`
+	// satisfies `pred`. Supports `from` being greater than `to`.
 	function findFirst(pred, from, to) {
+	  // At any point we are certain `to` satisfies `pred`, don't know
+	  // whether `from` does.
+	  var dir = from > to ? -1 : 1
 	  for (;;) {
-	    if (Math.abs(from - to) <= 1) { return pred(from) ? from : to }
-	    var mid = Math.floor((from + to) / 2)
+	    if (from == to) { return from }
+	    var midF = (from + to) / 2, mid = dir < 0 ? Math.ceil(midF) : Math.floor(midF)
+	    if (mid == from) { return pred(mid) ? from : to }
 	    if (pred(mid)) { to = mid }
-	    else { from = mid }
+	    else { from = mid + dir }
 	  }
 	}
 
 	// The display handles the DOM integration, both for input reading
 	// and content drawing. It holds references to DOM nodes and
 	// display-related state.
 
 	function Display(place, doc, input) {
@@ -1134,22 +1139,22 @@ var CodeMirror =
 	      d.maxLine = line
 	    }
 	  })
 	}
 
 	// BIDI HELPERS
 
 	function iterateBidiSections(order, from, to, f) {
-	  if (!order) { return f(from, to, "ltr") }
+	  if (!order) { return f(from, to, "ltr", 0) }
 	  var found = false
 	  for (var i = 0; i < order.length; ++i) {
 	    var part = order[i]
 	    if (part.from < to && part.to > from || from == to && part.to == from) {
-	      f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr")
+	      f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr", i)
 	      found = true
 	    }
 	  }
 	  if (!found) { f(from, to, "ltr") }
 	}
 
 	var bidiOther = null
 	function getBidiPartAt(order, ch, sticky) {
@@ -1342,122 +1347,16 @@ var CodeMirror =
 	// false for lines that are fully left-to-right, and an array of
 	// BidiSpan objects otherwise.
 	function getOrder(line, direction) {
 	  var order = line.order
 	  if (order == null) { order = line.order = bidiOrdering(line.text, direction) }
 	  return order
 	}
 
-	function moveCharLogically(line, ch, dir) {
-	  var target = skipExtendingChars(line.text, ch + dir, dir)
-	  return target < 0 || target > line.text.length ? null : target
-	}
-
-	function moveLogically(line, start, dir) {
-	  var ch = moveCharLogically(line, start.ch, dir)
-	  return ch == null ? null : new Pos(start.line, ch, dir < 0 ? "after" : "before")
-	}
-
-	function endOfLine(visually, cm, lineObj, lineNo, dir) {
-	  if (visually) {
-	    var order = getOrder(lineObj, cm.doc.direction)
-	    if (order) {
-	      var part = dir < 0 ? lst(order) : order[0]
-	      var moveInStorageOrder = (dir < 0) == (part.level == 1)
-	      var sticky = moveInStorageOrder ? "after" : "before"
-	      var ch
-	      // With a wrapped rtl chunk (possibly spanning multiple bidi parts),
-	      // it could be that the last bidi part is not on the last visual line,
-	      // since visual lines contain content order-consecutive chunks.
-	      // Thus, in rtl, we are looking for the first (content-order) character
-	      // in the rtl chunk that is on the last line (that is, the same line
-	      // as the last (content-order) character).
-	      if (part.level > 0) {
-	        var prep = prepareMeasureForLine(cm, lineObj)
-	        ch = dir < 0 ? lineObj.text.length - 1 : 0
-	        var targetTop = measureCharPrepared(cm, prep, ch).top
-	        ch = findFirst(function (ch) { return measureCharPrepared(cm, prep, ch).top == targetTop; }, (dir < 0) == (part.level == 1) ? part.from : part.to - 1, ch)
-	        if (sticky == "before") { ch = moveCharLogically(lineObj, ch, 1) }
-	      } else { ch = dir < 0 ? part.to : part.from }
-	      return new Pos(lineNo, ch, sticky)
-	    }
-	  }
-	  return new Pos(lineNo, dir < 0 ? lineObj.text.length : 0, dir < 0 ? "before" : "after")
-	}
-
-	function moveVisually(cm, line, start, dir) {
-	  var bidi = getOrder(line, cm.doc.direction)
-	  if (!bidi) { return moveLogically(line, start, dir) }
-	  if (start.ch >= line.text.length) {
-	    start.ch = line.text.length
-	    start.sticky = "before"
-	  } else if (start.ch <= 0) {
-	    start.ch = 0
-	    start.sticky = "after"
-	  }
-	  var partPos = getBidiPartAt(bidi, start.ch, start.sticky), part = bidi[partPos]
-	  if (cm.doc.direction == "ltr" && part.level % 2 == 0 && (dir > 0 ? part.to > start.ch : part.from < start.ch)) {
-	    // Case 1: We move within an ltr part in an ltr editor. Even with wrapped lines,
-	    // nothing interesting happens.
-	    return moveLogically(line, start, dir)
-	  }
-
-	  var mv = function (pos, dir) { return moveCharLogically(line, pos instanceof Pos ? pos.ch : pos, dir); }
-	  var prep
-	  var getWrappedLineExtent = function (ch) {
-	    if (!cm.options.lineWrapping) { return {begin: 0, end: line.text.length} }
-	    prep = prep || prepareMeasureForLine(cm, line)
-	    return wrappedLineExtentChar(cm, line, prep, ch)
-	  }
-	  var wrappedLineExtent = getWrappedLineExtent(start.sticky == "before" ? mv(start, -1) : start.ch)
-
-	  if (cm.doc.direction == "rtl" || part.level == 1) {
-	    var moveInStorageOrder = (part.level == 1) == (dir < 0)
-	    var ch = mv(start, moveInStorageOrder ? 1 : -1)
-	    if (ch != null && (!moveInStorageOrder ? ch >= part.from && ch >= wrappedLineExtent.begin : ch <= part.to && ch <= wrappedLineExtent.end)) {
-	      // Case 2: We move within an rtl part or in an rtl editor on the same visual line
-	      var sticky = moveInStorageOrder ? "before" : "after"
-	      return new Pos(start.line, ch, sticky)
-	    }
-	  }
-
-	  // Case 3: Could not move within this bidi part in this visual line, so leave
-	  // the current bidi part
-
-	  var searchInVisualLine = function (partPos, dir, wrappedLineExtent) {
-	    var getRes = function (ch, moveInStorageOrder) { return moveInStorageOrder
-	      ? new Pos(start.line, mv(ch, 1), "before")
-	      : new Pos(start.line, ch, "after"); }
-
-	    for (; partPos >= 0 && partPos < bidi.length; partPos += dir) {
-	      var part = bidi[partPos]
-	      var moveInStorageOrder = (dir > 0) == (part.level != 1)
-	      var ch = moveInStorageOrder ? wrappedLineExtent.begin : mv(wrappedLineExtent.end, -1)
-	      if (part.from <= ch && ch < part.to) { return getRes(ch, moveInStorageOrder) }
-	      ch = moveInStorageOrder ? part.from : mv(part.to, -1)
-	      if (wrappedLineExtent.begin <= ch && ch < wrappedLineExtent.end) { return getRes(ch, moveInStorageOrder) }
-	    }
-	  }
-
-	  // Case 3a: Look for other bidi parts on the same visual line
-	  var res = searchInVisualLine(partPos + dir, dir, wrappedLineExtent)
-	  if (res) { return res }
-
-	  // Case 3b: Look for other bidi parts on the next visual line
-	  var nextCh = dir > 0 ? wrappedLineExtent.end : mv(wrappedLineExtent.begin, -1)
-	  if (nextCh != null && !(dir > 0 && nextCh == line.text.length)) {
-	    res = searchInVisualLine(dir > 0 ? 0 : bidi.length - 1, dir, getWrappedLineExtent(nextCh))
-	    if (res) { return res }
-	  }
-
-	  // Case 4: Nowhere to move
-	  return null
-	}
-
 	// EVENT HANDLING
 
 	// Lightweight event framework. on/off also work on DOM nodes,
 	// registering native DOM handlers.
 
 	var noHandlers = []
 
 	var on = function(emitter, type, f) {
@@ -2956,25 +2855,32 @@ var CodeMirror =
 	  if (chrome && android) { return -(document.body.getBoundingClientRect().left - parseInt(getComputedStyle(document.body).marginLeft)) }
 	  return window.pageXOffset || (document.documentElement || document.body).scrollLeft
 	}
 	function pageScrollY() {
 	  if (chrome && android) { return -(document.body.getBoundingClientRect().top - parseInt(getComputedStyle(document.body).marginTop)) }
 	  return window.pageYOffset || (document.documentElement || document.body).scrollTop
 	}
 
+	function widgetTopHeight(lineObj) {
+	  var height = 0
+	  if (lineObj.widgets) { for (var i = 0; i < lineObj.widgets.length; ++i) { if (lineObj.widgets[i].above)
+	    { height += widgetHeight(lineObj.widgets[i]) } } }
+	  return height
+	}
+
 	// Converts a {top, bottom, left, right} box from line-local
 	// coordinates into another coordinate system. Context may be one of
 	// "line", "div" (display.lineDiv), "local"./null (editor), "window",
 	// or "page".
 	function intoCoordSystem(cm, lineObj, rect, context, includeWidgets) {
-	  if (!includeWidgets && lineObj.widgets) { for (var i = 0; i < lineObj.widgets.length; ++i) { if (lineObj.widgets[i].above) {
-	    var size = widgetHeight(lineObj.widgets[i])
-	    rect.top += size; rect.bottom += size
-	  } } }
+	  if (!includeWidgets) {
+	    var height = widgetTopHeight(lineObj)
+	    rect.top += height; rect.bottom += height
+	  }
 	  if (context == "line") { return rect }
 	  if (!context) { context = "local" }
 	  var yOff = heightAtLine(lineObj)
 	  if (context == "local") { yOff += paddingTop(cm.display) }
 	  else { yOff -= cm.display.viewOffset }
 	  if (context == "page" || context == "window") {
 	    var lOff = cm.display.lineSpace.getBoundingClientRect()
 	    yOff += lOff.top + (context == "window" ? 0 : pageScrollY())
@@ -3039,17 +2945,17 @@ var CodeMirror =
 	    sticky = "before"
 	  } else if (ch <= 0) {
 	    ch = 0
 	    sticky = "after"
 	  }
 	  if (!order) { return get(sticky == "before" ? ch - 1 : ch, sticky == "before") }
 
 	  function getBidi(ch, partPos, invert) {
-	    var part = order[partPos], right = (part.level % 2) != 0
+	    var part = order[partPos], right = part.level == 1
 	    return get(invert ? ch - 1 : ch, right != invert)
 	  }
 	  var partPos = getBidiPartAt(order, ch, sticky)
 	  var other = bidiOther
 	  var val = getBidi(ch, partPos, sticky == "before")
 	  if (other != null) { val.other = getBidi(ch, other, sticky != "before") }
 	  return val
 	}
@@ -3097,87 +3003,156 @@ var CodeMirror =
 	    if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))
 	      { lineN = lineNo(lineObj = mergedPos.to.line) }
 	    else
 	      { return found }
 	  }
 	}
 
 	function wrappedLineExtent(cm, lineObj, preparedMeasure, y) {
-	  var measure = function (ch) { return intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, ch), "line"); }
+	  y -= widgetTopHeight(lineObj)
 	  var end = lineObj.text.length
-	  var begin = findFirst(function (ch) { return measure(ch - 1).bottom <= y; }, end, 0)
-	  end = findFirst(function (ch) { return measure(ch).top > y; }, begin, end)
+	  var begin = findFirst(function (ch) { return measureCharPrepared(cm, preparedMeasure, ch - 1).bottom <= y; }, end, 0)
+	  end = findFirst(function (ch) { return measureCharPrepared(cm, preparedMeasure, ch).top > y; }, begin, end)
 	  return {begin: begin, end: end}
 	}
 
 	function wrappedLineExtentChar(cm, lineObj, preparedMeasure, target) {
+	  if (!preparedMeasure) { preparedMeasure = prepareMeasureForLine(cm, lineObj) }
 	  var targetTop = intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, target), "line").top
 	  return wrappedLineExtent(cm, lineObj, preparedMeasure, targetTop)
 	}
 
+	// Returns true if the given side of a box is after the given
+	// coordinates, in top-to-bottom, left-to-right order.
+	function boxIsAfter(box, x, y, left) {
+	  return box.bottom <= y ? false : box.top > y ? true : (left ? box.left : box.right) > x
+	}
+
 	function coordsCharInner(cm, lineObj, lineNo, x, y) {
+	  // Move y into line-local coordinate space
 	  y -= heightAtLine(lineObj)
-	  var begin = 0, end = lineObj.text.length
 	  var preparedMeasure = prepareMeasureForLine(cm, lineObj)
-	  var pos
+	  // When directly calling `measureCharPrepared`, we have to adjust
+	  // for the widgets at this line.
+	  var widgetHeight = widgetTopHeight(lineObj)
+	  var begin = 0, end = lineObj.text.length, ltr = true
+
 	  var order = getOrder(lineObj, cm.doc.direction)
+	  // If the line isn't plain left-to-right text, first figure out
+	  // which bidi section the coordinates fall into.
 	  if (order) {
-	    if (cm.options.lineWrapping) {
-	      ;var assign;
-	      ((assign = wrappedLineExtent(cm, lineObj, preparedMeasure, y), begin = assign.begin, end = assign.end, assign))
-	    }
-	    pos = new Pos(lineNo, Math.floor(begin + (end - begin) / 2))
-	    var beginLeft = cursorCoords(cm, pos, "line", lineObj, preparedMeasure).left
-	    var dir = beginLeft < x ? 1 : -1
-	    var prevDiff, diff = beginLeft - x, prevPos
-	    var steps = Math.ceil((end - begin) / 4)
-	    outer: do {
-	      prevDiff = diff
-	      prevPos = pos
-	      var i = 0
-	      for (; i < steps; ++i) {
-	        var prevPos$1 = pos
-	        pos = moveVisually(cm, lineObj, pos, dir)
-	        if (pos == null || pos.ch < begin || end <= (pos.sticky == "before" ? pos.ch - 1 : pos.ch)) {
-	          pos = prevPos$1
-	          break outer
-	        }
-	      }
-	      diff = cursorCoords(cm, pos, "line", lineObj, preparedMeasure).left - x
-	      if (steps > 1) {
-	        var diff_change_per_step = Math.abs(diff - prevDiff) / steps
-	        steps = Math.min(steps, Math.ceil(Math.abs(diff) / diff_change_per_step))
-	        dir = diff < 0 ? 1 : -1
-	      }
-	    } while (diff != 0 && (steps > 1 || ((dir < 0) != (diff < 0) && (Math.abs(diff) <= Math.abs(prevDiff)))))
-	    if (Math.abs(diff) > Math.abs(prevDiff)) {
-	      if ((diff < 0) == (prevDiff < 0)) { throw new Error("Broke out of infinite loop in coordsCharInner") }
-	      pos = prevPos
-	    }
+	    var part = (cm.options.lineWrapping ? coordsBidiPartWrapped : coordsBidiPart)
+	                 (cm, lineObj, lineNo, preparedMeasure, order, x, y)
+	    ltr = part.level != 1
+	    // The awkward -1 offsets are needed because findFirst (called
+	    // on these below) will treat its first bound as inclusive,
+	    // second as exclusive, but we want to actually address the
+	    // characters in the part's range
+	    begin = ltr ? part.from : part.to - 1
+	    end = ltr ? part.to : part.from - 1
+	  }
+
+	  // A binary search to find the first character whose bounding box
+	  // starts after the coordinates. If we run across any whose box wrap
+	  // the coordinates, store that.
+	  var chAround = null, boxAround = null
+	  var ch = findFirst(function (ch) {
+	    var box = measureCharPrepared(cm, preparedMeasure, ch)
+	    box.top += widgetHeight; box.bottom += widgetHeight
+	    if (!boxIsAfter(box, x, y, false)) { return false }
+	    if (box.top <= y && box.left <= x) {
+	      chAround = ch
+	      boxAround = box
+	    }
+	    return true
+	  }, begin, end)
+
+	  var baseX, sticky, outside = false
+	  // If a box around the coordinates was found, use that
+	  if (boxAround) {
+	    // Distinguish coordinates nearer to the left or right side of the box
+	    var atLeft = x - boxAround.left < boxAround.right - x, atStart = atLeft == ltr
+	    ch = chAround + (atStart ? 0 : 1)
+	    sticky = atStart ? "after" : "before"
+	    baseX = atLeft ? boxAround.left : boxAround.right
 	  } else {
-	    var ch = findFirst(function (ch) {
-	      var box = intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, ch), "line")
-	      if (box.top > y) {
-	        // For the cursor stickiness
-	        end = Math.min(ch, end)
-	        return true
-	      }
-	      else if (box.bottom <= y) { return false }
-	      else if (box.left > x) { return true }
-	      else if (box.right < x) { return false }
-	      else { return (x - box.left < box.right - x) }
-	    }, begin, end)
-	    ch = skipExtendingChars(lineObj.text, ch, 1)
-	    pos = new Pos(lineNo, ch, ch == end ? "before" : "after")
-	  }
-	  var coords = cursorCoords(cm, pos, "line", lineObj, preparedMeasure)
-	  if (y < coords.top || coords.bottom < y) { pos.outside = true }
-	  pos.xRel = x < coords.left ? -1 : (x > coords.right ? 1 : 0)
-	  return pos
+	    // (Adjust for extended bound, if necessary.)
+	    if (!ltr && (ch == end || ch == begin)) { ch++ }
+	    // To determine which side to associate with, get the box to the
+	    // left of the character and compare it's vertical position to the
+	    // coordinates
+	    sticky = ch == 0 ? "after" : ch == lineObj.text.length ? "before" :
+	      (measureCharPrepared(cm, preparedMeasure, ch - (ltr ? 1 : 0)).bottom + widgetHeight <= y) == ltr ?
+	      "after" : "before"
+	    // Now get accurate coordinates for this place, in order to get a
+	    // base X position
+	    var coords = cursorCoords(cm, Pos(lineNo, ch, sticky), "line", lineObj, preparedMeasure)
+	    baseX = coords.left
+	    outside = y < coords.top || y >= coords.bottom
+	  }
+
+	  ch = skipExtendingChars(lineObj.text, ch, 1)
+	  return PosWithInfo(lineNo, ch, sticky, outside, x - baseX)
+	}
+
+	function coordsBidiPart(cm, lineObj, lineNo, preparedMeasure, order, x, y) {
+	  // Bidi parts are sorted left-to-right, and in a non-line-wrapping
+	  // situation, we can take this ordering to correspond to the visual
+	  // ordering. This finds the first part whose end is after the given
+	  // coordinates.
+	  var index = findFirst(function (i) {
+	    var part = order[i], ltr = part.level != 1
+	    return boxIsAfter(cursorCoords(cm, Pos(lineNo, ltr ? part.to : part.from, ltr ? "before" : "after"),
+	                                   "line", lineObj, preparedMeasure), x, y, true)
+	  }, 0, order.length - 1)
+	  var part = order[index]
+	  // If this isn't the first part, the part's start is also after
+	  // the coordinates, and the coordinates aren't on the same line as
+	  // that start, move one part back.
+	  if (index > 0) {
+	    var ltr = part.level != 1
+	    var start = cursorCoords(cm, Pos(lineNo, ltr ? part.from : part.to, ltr ? "after" : "before"),
+	                             "line", lineObj, preparedMeasure)
+	    if (boxIsAfter(start, x, y, true) && start.top > y)
+	      { part = order[index - 1] }
+	  }
+	  return part
+	}
+
+	function coordsBidiPartWrapped(cm, lineObj, _lineNo, preparedMeasure, order, x, y) {
+	  // In a wrapped line, rtl text on wrapping boundaries can do things
+	  // that don't correspond to the ordering in our `order` array at
+	  // all, so a binary search doesn't work, and we want to return a
+	  // part that only spans one line so that the binary search in
+	  // coordsCharInner is safe. As such, we first find the extent of the
+	  // wrapped line, and then do a flat search in which we discard any
+	  // spans that aren't on the line.
+	  var ref = wrappedLineExtent(cm, lineObj, preparedMeasure, y);
+	  var begin = ref.begin;
+	  var end = ref.end;
+	  var part = null, closestDist = null
+	  for (var i = 0; i < order.length; i++) {
+	    var p = order[i]
+	    if (p.from >= end || p.to <= begin) { continue }
+	    var ltr = p.level != 1
+	    var endX = measureCharPrepared(cm, preparedMeasure, ltr ? Math.min(end, p.to) - 1 : Math.max(begin, p.from)).right
+	    // Weigh against spans ending before this, so that they are only
+	    // picked if nothing ends after
+	    var dist = endX < x ? x - endX + 1e9 : endX - x
+	    if (!part || closestDist > dist) {
+	      part = p
+	      closestDist = dist
+	    }
+	  }
+	  if (!part) { part = order[order.length - 1] }
+	  // Clip the part to the wrapped line.
+	  if (part.from < begin) { part = {from: begin, to: part.to, level: part.level} }
+	  if (part.to > end) { part = {from: part.from, to: end, level: part.level} }
+	  return part
 	}
 
 	var measureText
 	// Compute the default text height.
 	function textHeight(display) {
 	  if (display.cachedTextHeight != null) { return display.cachedTextHeight }
 	  if (measureText == null) {
 	    measureText = elt("pre")
@@ -3293,22 +3268,24 @@ var CodeMirror =
 	  }
 	}
 
 	function updateSelection(cm) {
 	  cm.display.input.showSelection(cm.display.input.prepareSelection())
 	}
 
 	function prepareSelection(cm, primary) {
+	  if ( primary === void 0 ) primary = true;
+
 	  var doc = cm.doc, result = {}
 	  var curFragment = result.cursors = document.createDocumentFragment()
 	  var selFragment = result.selection = document.createDocumentFragment()
 
 	  for (var i = 0; i < doc.sel.ranges.length; i++) {
-	    if (primary === false && i == doc.sel.primIndex) { continue }
+	    if (!primary && i == doc.sel.primIndex) { continue }
 	    var range = doc.sel.ranges[i]
 	    if (range.from().line >= cm.display.viewTo || range.to().line < cm.display.viewFrom) { continue }
 	    var collapsed = range.empty()
 	    if (collapsed || cm.options.showCursorWhenSelecting)
 	      { drawSelectionCursor(cm, range.head, curFragment) }
 	    if (!collapsed)
 	      { drawSelectionRange(cm, range, selFragment) }
 	  }
@@ -3329,16 +3306,18 @@ var CodeMirror =
 	    var otherCursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor"))
 	    otherCursor.style.display = ""
 	    otherCursor.style.left = pos.other.left + "px"
 	    otherCursor.style.top = pos.other.top + "px"
 	    otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px"
 	  }
 	}
 
+	function cmpCoords(a, b) { return a.top - b.top || a.left - b.left }
+
 	// Draws the given range as a highlighted selection
 	function drawSelectionRange(cm, range, output) {
 	  var display = cm.display, doc = cm.doc
 	  var fragment = document.createDocumentFragment()
 	  var padding = paddingH(cm.display), leftSide = padding.left
 	  var rightSide = Math.max(display.sizerWidth, displayWidth(cm) - display.sizer.offsetLeft) - padding.right
 
 	  function add(left, top, width, bottom) {
@@ -3351,40 +3330,58 @@ var CodeMirror =
 	  function drawForLine(line, fromArg, toArg) {
 	    var lineObj = getLine(doc, line)
 	    var lineLen = lineObj.text.length
 	    var start, end
 	    function coords(ch, bias) {
 	      return charCoords(cm, Pos(line, ch), "div", lineObj, bias)
 	    }
 
-	    iterateBidiSections(getOrder(lineObj, doc.direction), fromArg || 0, toArg == null ? lineLen : toArg, function (from, to, dir) {
-	      var leftPos = coords(from, "left"), rightPos, left, right
-	      if (from == to) {
-	        rightPos = leftPos
-	        left = right = leftPos.left
-	      } else {
-	        rightPos = coords(to - 1, "right")
-	        if (dir == "rtl") { var tmp = leftPos; leftPos = rightPos; rightPos = tmp }
-	        left = leftPos.left
-	        right = rightPos.right
-	      }
-	      if (fromArg == null && from == 0) { left = leftSide }
-	      if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part
-	        add(left, leftPos.top, null, leftPos.bottom)
-	        left = leftSide
-	        if (leftPos.bottom < rightPos.top) { add(left, leftPos.bottom, null, rightPos.top) }
-	      }
-	      if (toArg == null && to == lineLen) { right = rightSide }
-	      if (!start || leftPos.top < start.top || leftPos.top == start.top && leftPos.left < start.left)
-	        { start = leftPos }
-	      if (!end || rightPos.bottom > end.bottom || rightPos.bottom == end.bottom && rightPos.right > end.right)
-	        { end = rightPos }
-	      if (left < leftSide + 1) { left = leftSide }
-	      add(left, rightPos.top, right - left, rightPos.bottom)
+	    var order = getOrder(lineObj, doc.direction)
+	    iterateBidiSections(order, fromArg || 0, toArg == null ? lineLen : toArg, function (from, to, dir, i) {
+	      var fromPos = coords(from, dir == "ltr" ? "left" : "right")
+	      var toPos = coords(to - 1, dir == "ltr" ? "right" : "left")
+	      if (dir == "ltr") {
+	        var fromLeft = fromArg == null && from == 0 ? leftSide : fromPos.left
+	        var toRight = toArg == null && to == lineLen ? rightSide : toPos.right
+	        if (toPos.top - fromPos.top <= 3) { // Single line
+	          add(fromLeft, toPos.top, toRight - fromLeft, toPos.bottom)
+	        } else { // Multiple lines
+	          add(fromLeft, fromPos.top, null, fromPos.bottom)
+	          if (fromPos.bottom < toPos.top) { add(leftSide, fromPos.bottom, null, toPos.top) }
+	          add(leftSide, toPos.top, toPos.right, toPos.bottom)
+	        }
+	      } else if (from < to) { // RTL
+	        var fromRight = fromArg == null && from == 0 ? rightSide : fromPos.right
+	        var toLeft = toArg == null && to == lineLen ? leftSide : toPos.left
+	        if (toPos.top - fromPos.top <= 3) { // Single line
+	          add(toLeft, toPos.top, fromRight - toLeft, toPos.bottom)
+	        } else { // Multiple lines
+	          var topLeft = leftSide
+	          if (i) {
+	            var topEnd = wrappedLineExtentChar(cm, lineObj, null, from).end
+	            // The coordinates returned for an RTL wrapped space tend to
+	            // be complete bogus, so try to skip that here.
+	            topLeft = coords(topEnd - (/\s/.test(lineObj.text.charAt(topEnd - 1)) ? 2 : 1), "left").left
+	          }
+	          add(topLeft, fromPos.top, fromRight - topLeft, fromPos.bottom)
+	          if (fromPos.bottom < toPos.top) { add(leftSide, fromPos.bottom, null, toPos.top) }
+	          var botWidth = null
+	          if (i < order.length  - 1 || true) {
+	            var botStart = wrappedLineExtentChar(cm, lineObj, null, to).begin
+	            botWidth = coords(botStart, "right").right - toLeft
+	          }
+	          add(toLeft, toPos.top, botWidth, toPos.bottom)
+	        }
+	      }
+
+	      if (!start || cmpCoords(fromPos, start) < 0) { start = fromPos }
+	      if (cmpCoords(toPos, start) < 0) { start = toPos }
+	      if (!end || cmpCoords(fromPos, end) < 0) { end = fromPos }
+	      if (cmpCoords(toPos, end) < 0) { end = toPos }
 	    })
 	    return {start: start, end: end}
 	  }
 
 	  var sFrom = range.from(), sTo = range.to()
 	  if (sFrom.line == sTo.line) {
 	    drawForLine(sFrom.line, sFrom.ch, sTo.ch)
 	  } else {
@@ -4004,30 +4001,30 @@ var CodeMirror =
 	    op.adjustWidthTo = measureChar(cm, display.maxLine, display.maxLine.text.length).left + 3
 	    cm.display.sizerWidth = op.adjustWidthTo
 	    op.barMeasure.scrollWidth =
 	      Math.max(display.scroller.clientWidth, display.sizer.offsetLeft + op.adjustWidthTo + scrollGap(cm) + cm.display.barWidth)
 	    op.maxScrollLeft = Math.max(0, display.sizer.offsetLeft + op.adjustWidthTo - displayWidth(cm))
 	  }
 
 	  if (op.updatedDisplay || op.selectionChanged)
-	    { op.preparedSelection = display.input.prepareSelection(op.focus) }
+	    { op.preparedSelection = display.input.prepareSelection() }
 	}
 
 	function endOperation_W2(op) {
 	  var cm = op.cm
 
 	  if (op.adjustWidthTo != null) {
 	    cm.display.sizer.style.minWidth = op.adjustWidthTo + "px"
 	    if (op.maxScrollLeft < cm.doc.scrollLeft)
 	      { setScrollLeft(cm, Math.min(cm.display.scroller.scrollLeft, op.maxScrollLeft), true) }
 	    cm.display.maxLineChanged = false
 	  }
 
-	  var takeFocus = op.focus && op.focus == activeElt() && (!document.hasFocus || document.hasFocus())
+	  var takeFocus = op.focus && op.focus == activeElt()
 	  if (op.preparedSelection)
 	    { cm.display.input.showSelection(op.preparedSelection, takeFocus) }
 	  if (op.updatedDisplay || op.startHeight != cm.doc.height)
 	    { updateScrollbars(cm, op.barMeasure) }
 	  if (op.updatedDisplay)
 	    { setDocumentHeight(cm, op.barMeasure) }
 
 	  if (op.selectionChanged) { restartBlink(cm) }
@@ -5606,17 +5603,18 @@ var CodeMirror =
 	    if (changeHandler) { signalLater(cm, "change", cm, obj) }
 	    if (changesHandler) { (cm.curOp.changeObjs || (cm.curOp.changeObjs = [])).push(obj) }
 	  }
 	  cm.display.selForContextMenu = null
 	}
 
 	function replaceRange(doc, code, from, to, origin) {
 	  if (!to) { to = from }
-	  if (cmp(to, from) < 0) { var tmp = to; to = from; from = tmp }
+	  if (cmp(to, from) < 0) { var assign;
+	    (assign = [to, from], from = assign[0], to = assign[1], assign) }
 	  if (typeof code == "string") { code = doc.splitLines(code) }
 	  makeChange(doc, {from: from, to: to, text: code, origin: origin})
 	}
 
 	// Rebasing/resetting history to deal with externally-sourced changes
 
 	function rebaseHistSelSingle(pos, from, to, diff) {
 	  if (to < pos.line) {
@@ -6968,16 +6966,122 @@ var CodeMirror =
 	  // Next, remove those actual ranges.
 	  runInOp(cm, function () {
 	    for (var i = kill.length - 1; i >= 0; i--)
 	      { replaceRange(cm.doc, "", kill[i].from, kill[i].to, "+delete") }
 	    ensureCursorVisible(cm)
 	  })
 	}
 
+	function moveCharLogically(line, ch, dir) {
+	  var target = skipExtendingChars(line.text, ch + dir, dir)
+	  return target < 0 || target > line.text.length ? null : target
+	}
+
+	function moveLogically(line, start, dir) {
+	  var ch = moveCharLogically(line, start.ch, dir)
+	  return ch == null ? null : new Pos(start.line, ch, dir < 0 ? "after" : "before")
+	}
+
+	function endOfLine(visually, cm, lineObj, lineNo, dir) {
+	  if (visually) {
+	    var order = getOrder(lineObj, cm.doc.direction)
+	    if (order) {
+	      var part = dir < 0 ? lst(order) : order[0]
+	      var moveInStorageOrder = (dir < 0) == (part.level == 1)
+	      var sticky = moveInStorageOrder ? "after" : "before"
+	      var ch
+	      // With a wrapped rtl chunk (possibly spanning multiple bidi parts),
+	      // it could be that the last bidi part is not on the last visual line,
+	      // since visual lines contain content order-consecutive chunks.
+	      // Thus, in rtl, we are looking for the first (content-order) character
+	      // in the rtl chunk that is on the last line (that is, the same line
+	      // as the last (content-order) character).
+	      if (part.level > 0) {
+	        var prep = prepareMeasureForLine(cm, lineObj)
+	        ch = dir < 0 ? lineObj.text.length - 1 : 0
+	        var targetTop = measureCharPrepared(cm, prep, ch).top
+	        ch = findFirst(function (ch) { return measureCharPrepared(cm, prep, ch).top == targetTop; }, (dir < 0) == (part.level == 1) ? part.from : part.to - 1, ch)
+	        if (sticky == "before") { ch = moveCharLogically(lineObj, ch, 1) }
+	      } else { ch = dir < 0 ? part.to : part.from }
+	      return new Pos(lineNo, ch, sticky)
+	    }
+	  }
+	  return new Pos(lineNo, dir < 0 ? lineObj.text.length : 0, dir < 0 ? "before" : "after")
+	}
+
+	function moveVisually(cm, line, start, dir) {
+	  var bidi = getOrder(line, cm.doc.direction)
+	  if (!bidi) { return moveLogically(line, start, dir) }
+	  if (start.ch >= line.text.length) {
+	    start.ch = line.text.length
+	    start.sticky = "before"
+	  } else if (start.ch <= 0) {
+	    start.ch = 0
+	    start.sticky = "after"
+	  }
+	  var partPos = getBidiPartAt(bidi, start.ch, start.sticky), part = bidi[partPos]
+	  if (cm.doc.direction == "ltr" && part.level % 2 == 0 && (dir > 0 ? part.to > start.ch : part.from < start.ch)) {
+	    // Case 1: We move within an ltr part in an ltr editor. Even with wrapped lines,
+	    // nothing interesting happens.
+	    return moveLogically(line, start, dir)
+	  }
+
+	  var mv = function (pos, dir) { return moveCharLogically(line, pos instanceof Pos ? pos.ch : pos, dir); }
+	  var prep
+	  var getWrappedLineExtent = function (ch) {
+	    if (!cm.options.lineWrapping) { return {begin: 0, end: line.text.length} }
+	    prep = prep || prepareMeasureForLine(cm, line)
+	    return wrappedLineExtentChar(cm, line, prep, ch)
+	  }
+	  var wrappedLineExtent = getWrappedLineExtent(start.sticky == "before" ? mv(start, -1) : start.ch)
+
+	  if (cm.doc.direction == "rtl" || part.level == 1) {
+	    var moveInStorageOrder = (part.level == 1) == (dir < 0)
+	    var ch = mv(start, moveInStorageOrder ? 1 : -1)
+	    if (ch != null && (!moveInStorageOrder ? ch >= part.from && ch >= wrappedLineExtent.begin : ch <= part.to && ch <= wrappedLineExtent.end)) {
+	      // Case 2: We move within an rtl part or in an rtl editor on the same visual line
+	      var sticky = moveInStorageOrder ? "before" : "after"
+	      return new Pos(start.line, ch, sticky)
+	    }
+	  }
+
+	  // Case 3: Could not move within this bidi part in this visual line, so leave
+	  // the current bidi part
+
+	  var searchInVisualLine = function (partPos, dir, wrappedLineExtent) {
+	    var getRes = function (ch, moveInStorageOrder) { return moveInStorageOrder
+	      ? new Pos(start.line, mv(ch, 1), "before")
+	      : new Pos(start.line, ch, "after"); }
+
+	    for (; partPos >= 0 && partPos < bidi.length; partPos += dir) {
+	      var part = bidi[partPos]
+	      var moveInStorageOrder = (dir > 0) == (part.level != 1)
+	      var ch = moveInStorageOrder ? wrappedLineExtent.begin : mv(wrappedLineExtent.end, -1)
+	      if (part.from <= ch && ch < part.to) { return getRes(ch, moveInStorageOrder) }
+	      ch = moveInStorageOrder ? part.from : mv(part.to, -1)
+	      if (wrappedLineExtent.begin <= ch && ch < wrappedLineExtent.end) { return getRes(ch, moveInStorageOrder) }
+	    }
+	  }
+
+	  // Case 3a: Look for other bidi parts on the same visual line
+	  var res = searchInVisualLine(partPos + dir, dir, wrappedLineExtent)
+	  if (res) { return res }
+
+	  // Case 3b: Look for other bidi parts on the next visual line
+	  var nextCh = dir > 0 ? wrappedLineExtent.end : mv(wrappedLineExtent.begin, -1)
+	  if (nextCh != null && !(dir > 0 && nextCh == line.text.length)) {
+	    res = searchInVisualLine(dir > 0 ? 0 : bidi.length - 1, dir, getWrappedLineExtent(nextCh))
+	    if (res) { return res }
+	  }
+
+	  // Case 4: Nowhere to move
+	  return null
+	}
+
 	// Commands are parameter-less actions that can be performed on an
 	// editor, mostly used for keybindings.
 	var commands = {
 	  selectAll: selectAll,
 	  singleSelection: function (cm) { return cm.setSelection(cm.getCursor("anchor"), cm.getCursor("head"), sel_dontScroll); },
 	  killLine: function (cm) { return deleteNearSelection(cm, function (range) {
 	    if (range.empty()) {
 	      var len = getLine(cm.doc, range.head.line).text.length
@@ -7529,17 +7633,17 @@ var CodeMirror =
 	      if (cmp(range.anchor, anchor) > 0) {
 	        head = range.head
 	        anchor = minPos(oldRange.from(), range.anchor)
 	      } else {
 	        head = range.anchor
 	        anchor = maxPos(oldRange.to(), range.head)
 	      }
 	      var ranges$1 = startSel.ranges.slice(0)
-	      ranges$1[ourIndex] = new Range(clipPos(doc, anchor), head)
+	      ranges$1[ourIndex] = bidiSimplify(cm, new Range(clipPos(doc, anchor), head))
 	      setSelection(doc, normalizeSelection(ranges$1, ourIndex), sel_mouse)
 	    }
 	  }
 
 	  var editorSize = display.wrapper.getBoundingClientRect()
 	  // Used to ensure timeout re-tries don't fire when another extend
 	  // happened in the meantime (clearTimeout isn't reliable -- at
 	  // least on Chrome, the timeouts still happen even when cleared,
@@ -7581,23 +7685,62 @@ var CodeMirror =
 	    else { extend(e) }
 	  })
 	  var up = operation(cm, done)
 	  cm.state.selectingText = up
 	  on(document, "mousemove", move)
 	  on(document, "mouseup", up)
 	}
 
+	// Used when mouse-selecting to adjust the anchor to the proper side
+	// of a bidi jump depending on the visual position of the head.
+	function bidiSimplify(cm, range) {
+	  var anchor = range.anchor;
+	  var head = range.head;
+	  var anchorLine = getLine(cm.doc, anchor.line)
+	  if (cmp(anchor, head) == 0 && anchor.sticky == head.sticky) { return range }
+	  var order = getOrder(anchorLine)
+	  if (!order) { return range }
+	  var index = getBidiPartAt(order, anchor.ch, anchor.sticky), part = order[index]
+	  if (part.from != anchor.ch && part.to != anchor.ch) { return range }
+	  var boundary = index + ((part.from == anchor.ch) == (part.level != 1) ? 0 : 1)
+	  if (boundary == 0 || boundary == order.length) { return range }
+
+	  // Compute the relative visual position of the head compared to the
+	  // anchor (<0 is to the left, >0 to the right)
+	  var leftSide
+	  if (head.line != anchor.line) {
+	    leftSide = (head.line - anchor.line) * (cm.doc.direction == "ltr" ? 1 : -1) > 0
+	  } else {
+	    var headIndex = getBidiPartAt(order, head.ch, head.sticky)
+	    var dir = headIndex - index || (head.ch - anchor.ch) * (part.level == 1 ? -1 : 1)
+	    if (headIndex == boundary - 1 || headIndex == boundary)
+	      { leftSide = dir < 0 }
+	    else
+	      { leftSide = dir > 0 }
+	  }
+
+	  var usePart = order[boundary + (leftSide ? -1 : 0)]
+	  var from = leftSide == (usePart.level == 1)
+	  var ch = from ? usePart.from : usePart.to, sticky = from ? "after" : "before"
+	  return anchor.ch == ch && anchor.sticky == sticky ? range : new Range(new Pos(anchor.line, ch, sticky), head)
+	}
+
 
 	// Determines whether an event happened in the gutter, and fires the
 	// handlers for the corresponding event.
 	function gutterEvent(cm, e, type, prevent) {
 	  var mX, mY
-	  try { mX = e.clientX; mY = e.clientY }
-	  catch(e) { return false }
+	  if (e.touches) {
+	    mX = e.touches[0].clientX
+	    mY = e.touches[0].clientY
+	  } else {
+	    try { mX = e.clientX; mY = e.clientY }
+	    catch(e) { return false }
+	  }
 	  if (mX >= Math.floor(cm.display.gutters.getBoundingClientRect().right)) { return false }
 	  if (prevent) { e_preventDefault(e) }
 
 	  var display = cm.display
 	  var lineBox = display.lineDiv.getBoundingClientRect()
 
 	  if (mY > lineBox.bottom || !hasHandler(cm, type)) { return e_defaultPrevented(e) }
 	  mY -= lineBox.top - display.viewOffset
@@ -7925,17 +8068,17 @@ var CodeMirror =
 	    return touch.radiusX <= 1 && touch.radiusY <= 1
 	  }
 	  function farAway(touch, other) {
 	    if (other.left == null) { return true }
 	    var dx = other.left - touch.left, dy = other.top - touch.top
 	    return dx * dx + dy * dy > 20 * 20
 	  }
 	  on(d.scroller, "touchstart", function (e) {
-	    if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e)) {
+	    if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e) && !clickInGutter(cm, e)) {
 	      d.input.ensurePolled()
 	      clearTimeout(touchFinished)
 	      var now = +new Date
 	      d.activeTouch = {start: now, moved: false,
 	                       prev: now - prevTouch.end <= 300 ? prevTouch : null}
 	      if (e.touches.length == 1) {
 	        d.activeTouch.left = e.touches[0].pageX
 	        d.activeTouch.top = e.touches[0].pageY
@@ -9709,17 +9852,17 @@ var CodeMirror =
 	CodeMirror.defineDocExtension = function (name, func) {
 	  Doc.prototype[name] = func
 	}
 
 	CodeMirror.fromTextArea = fromTextArea
 
 	addLegacyProps(CodeMirror)
 
-	CodeMirror.version = "5.29.0"
+	CodeMirror.version = "5.30.0"
 
 	return CodeMirror;
 
 	})));
 
 /***/ }),
 /* 3 */
 /***/ (function(module, exports, __webpack_require__) {
@@ -10148,16 +10291,17 @@ var CodeMirror =
 	      queryDialog = doc.createElement("div");
 	      queryDialog.appendChild(inp);
 	      queryDialog.style.display = "flex";
 	    }
 
 	    var state = getSearchState(cm);
 	    if (state.query) return findNext(cm, rev);
 	    var q = cm.getSelection() || state.lastQuery;
+	    if (q instanceof RegExp && q.source == "x^") q = null
 	    if (persistent && cm.openDialog) {
 	      var hiding = null
 	      var searchNext = function(query, event) {
 	        CodeMirror.e_stop(event);
 	        if (!query) return;
 	        if (query != state.queryText) {
 	          startSearch(cm, state, query);
 	          state.posFrom = state.posTo = cm.getCursor();
@@ -10457,31 +10601,36 @@ var CodeMirror =
 	  var Pos = CodeMirror.Pos;
 
 	  CodeMirror.defineOption("autoCloseBrackets", false, function(cm, val, old) {
 	    if (old && old != CodeMirror.Init) {
 	      cm.removeKeyMap(keyMap);
 	      cm.state.closeBrackets = null;
 	    }
 	    if (val) {
+	      ensureBound(getOption(val, "pairs"))
 	      cm.state.closeBrackets = val;
 	      cm.addKeyMap(keyMap);
 	    }
 	  });
 
 	  function getOption(conf, name) {
 	    if (name == "pairs" && typeof conf == "string") return conf;
 	    if (typeof conf == "object" && conf[name] != null) return conf[name];
 	    return defaults[name];
 	  }
 
-	  var bind = defaults.pairs + "`";
 	  var keyMap = {Backspace: handleBackspace, Enter: handleEnter};
-	  for (var i = 0; i < bind.length; i++)
-	    keyMap["'" + bind.charAt(i) + "'"] = handler(bind.charAt(i));
+	  function ensureBound(chars) {
+	    for (var i = 0; i < chars.length; i++) {
+	      var ch = chars.charAt(i), key = "'" + ch + "'"
+	      if (!keyMap[key]) keyMap[key] = handler(ch)
+	    }
+	  }
+	  ensureBound(defaults.pairs + "`")
 
 	  function handler(ch) {
 	    return function(cm) { return handleChar(cm, ch); };
 	  }
 
 	  function getConfig(cm) {
 	    var deflt = cm.state.closeBrackets;
 	    if (!deflt || deflt.override) return deflt;
@@ -10889,17 +11038,17 @@ var CodeMirror =
 
 	  var keywords = function(){
 	    function kw(type) {return {type: type, style: "keyword"};}
 	    var A = kw("keyword a"), B = kw("keyword b"), C = kw("keyword c");
 	    var operator = kw("operator"), atom = {type: "atom", style: "atom"};
 
 	    var jsKeywords = {
 	      "if": kw("if"), "while": A, "with": A, "else": B, "do": B, "try": B, "finally": B,
-	      "return": C, "break": C, "continue": C, "new": kw("new"), "delete": C, "throw": C, "debugger": C,
+	      "return": C, "break": C, "continue": C, "new": kw("new"), "delete": C, "void": C, "throw": C, "debugger": C,
 	      "var": kw("var"), "const": kw("var"), "let": kw("var"),
 	      "function": kw("function"), "catch": kw("catch"),
 	      "for": kw("for"), "switch": kw("switch"), "case": kw("case"), "default": kw("default"),
 	      "in": operator, "typeof": operator, "instanceof": operator,
 	      "true": atom, "false": atom, "null": atom, "undefined": atom, "NaN": atom, "Infinity": atom,
 	      "this": kw("this"), "class": kw("class"), "super": kw("atom"),
 	      "yield": C, "export": kw("export"), "import": kw("import"), "extends": C,
 	      "await": C
@@ -11259,17 +11408,17 @@ var CodeMirror =
 	  }
 	  function parenExpr(type) {
 	    if (type != "(") return pass()
 	    return cont(pushlex(")"), expression, expect(")"), poplex)
 	  }
 	  function expressionInner(type, noComma) {
 	    if (cx.state.fatArrowAt == cx.stream.start) {
 	      var body = noComma ? arrowBodyNoComma : arrowBody;
-	      if (type == "(") return cont(pushcontext, pushlex(")"), commasep(pattern, ")"), poplex, expect("=>"), body, popcontext);
+	      if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, expect("=>"), body, popcontext);
 	      else if (type == "variable") return pass(pushcontext, pattern, expect("=>"), body, popcontext);
 	    }
 
 	    var maybeop = noComma ? maybeoperatorNoComma : maybeoperatorComma;
 	    if (atomicTypes.hasOwnProperty(type)) return cont(maybeop);
 	    if (type == "function") return cont(functiondef, maybeop);
 	    if (type == "class") return cont(pushlex("form"), classExpression, poplex);
 	    if (type == "keyword c" || type == "async") return cont(noComma ? maybeexpressionNoComma : maybeexpression);
@@ -11304,16 +11453,21 @@ var CodeMirror =
 	      return cont(expr);
 	    }
 	    if (type == "quasi") { return pass(quasi, me); }
 	    if (type == ";") return;
 	    if (type == "(") return contCommasep(expressionNoComma, ")", "call", me);
 	    if (type == ".") return cont(property, me);
 	    if (type == "[") return cont(pushlex("]"), maybeexpression, expect("]"), poplex, me);
 	    if (isTS && value == "as") { cx.marked = "keyword"; return cont(typeexpr, me) }
+	    if (type == "regexp") {
+	      cx.state.lastType = cx.marked = "operator"
+	      cx.stream.backUp(cx.stream.pos - cx.stream.start - 1)
+	      return cont(expr)
+	    }
 	  }
 	  function quasi(type, value) {
 	    if (type != "quasi") return pass();
 	    if (value.slice(value.length - 2) != "${") return cont(quasi);
 	    return cont(expression, continueQuasi);
 	  }
 	  function continueQuasi(type) {
 	    if (type == "}") {
@@ -11352,16 +11506,19 @@ var CodeMirror =
 	  }
 	  function objprop(type, value) {
 	    if (type == "async") {
 	      cx.marked = "property";
 	      return cont(objprop);
 	    } else if (type == "variable" || cx.style == "keyword") {
 	      cx.marked = "property";
 	      if (value == "get" || value == "set") return cont(getterSetter);
+	      var m // Work around fat-arrow-detection complication for detecting typescript typed arrow params
+	      if (isTS && cx.state.fatArrowAt == cx.stream.start && (m = cx.stream.match(/^\s*:\s*/, false)))
+	        cx.state.fatArrowAt = cx.stream.pos + m[0].length
 	      return cont(afterprop);
 	    } else if (type == "number" || type == "string") {
 	      cx.marked = jsonldMode ? "property" : (cx.style + " property");
 	      return cont(afterprop);
 	    } else if (type == "jsonld-keyword") {
 	      return cont(afterprop);
 	    } else if (type == "modifier") {
 	      return cont(objprop)
@@ -11509,17 +11666,18 @@ var CodeMirror =
 	    if (type != ")") cont(expression);
 	  }
 	  function functiondef(type, value) {
 	    if (value == "*") {cx.marked = "keyword"; return cont(functiondef);}
 	    if (type == "variable") {register(value); return cont(functiondef);}
 	    if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, maybetype, statement, popcontext);
 	    if (isTS && value == "<") return cont(pushlex(">"), commasep(typeexpr, ">"), poplex, functiondef)
 	  }
-	  function funarg(type) {
+	  function funarg(type, value) {
+	    if (value == "@") cont(expression, funarg)
 	    if (type == "spread" || type == "modifier") return cont(funarg);
 	    return pass(pattern, maybetype, maybeAssign);
 	  }
 	  function classExpression(type, value) {
 	    // Class expressions may have an optional name.
 	    if (type == "variable") return className(type, value);
 	    return classNameAfter(type, value);
 	  }
@@ -11535,17 +11693,17 @@ var CodeMirror =
 	  function classBody(type, value) {
 	    if (type == "modifier" || type == "async" ||
 	        (type == "variable" &&
 	         (value == "static" || value == "get" || value == "set") &&
 	         cx.stream.match(/^\s+[\w$\xa1-\uffff]/, false))) {
 	      cx.marked = "keyword";
 	      return cont(classBody);
 	    }
-	    if (type == "variable") {
+	    if (type == "variable" || cx.style == "keyword") {
 	      cx.marked = "property";
 	      return cont(isTS ? classfield : functiondef, classBody);
 	    }
 	    if (type == "[")
 	      return cont(expression, expect("]"), isTS ? classfield : functiondef, classBody)
 	    if (value == "*") {
 	      cx.marked = "keyword";
 	      return cont(classBody);
@@ -11597,17 +11755,17 @@ var CodeMirror =
 	  function isContinuedStatement(state, textAfter) {
 	    return state.lastType == "operator" || state.lastType == "," ||
 	      isOperatorChar.test(textAfter.charAt(0)) ||
 	      /[,.]/.test(textAfter.charAt(0));
 	  }
 
 	  function expressionAllowed(stream, state, backUp) {
 	    return state.tokenize == tokenBase &&
-	      /^(?:operator|sof|keyword c|case|new|export|default|[\[{}\(,;:]|=>)$/.test(state.lastType) ||
+	      /^(?:operator|sof|keyword [bc]|case|new|export|default|spread|[\[{}\(,;:]|=>)$/.test(state.lastType) ||
 	      (state.lastType == "quasi" && /\{\s*$/.test(stream.string.slice(0, stream.pos - (backUp || 0))))
 	  }
 
 	  // Interface
 
 	  return {
 	    startState: function(basecolumn) {
 	      var state = {

--- a/devtools/client/sourceeditor/codemirror/lib/codemirror.js
+++ b/devtools/client/sourceeditor/codemirror/lib/codemirror.js
@@ -273,23 +273,28 @@ function isExtendingChar(ch) { return ch
 
 // Returns a number from the range [`0`; `str.length`] unless `pos` is outside that range.
 function skipExtendingChars(str, pos, dir) {
   while ((dir < 0 ? pos > 0 : pos < str.length) && isExtendingChar(str.charAt(pos))) { pos += dir }
   return pos
 }
 
 // Returns the value from the range [`from`; `to`] that satisfies
-// `pred` and is closest to `from`. Assumes that at least `to` satisfies `pred`.
+// `pred` and is closest to `from`. Assumes that at least `to`
+// satisfies `pred`. Supports `from` being greater than `to`.
 function findFirst(pred, from, to) {
+  // At any point we are certain `to` satisfies `pred`, don't know
+  // whether `from` does.
+  var dir = from > to ? -1 : 1
   for (;;) {
-    if (Math.abs(from - to) <= 1) { return pred(from) ? from : to }
-    var mid = Math.floor((from + to) / 2)
+    if (from == to) { return from }
+    var midF = (from + to) / 2, mid = dir < 0 ? Math.ceil(midF) : Math.floor(midF)
+    if (mid == from) { return pred(mid) ? from : to }
     if (pred(mid)) { to = mid }
-    else { from = mid }
+    else { from = mid + dir }
   }
 }
 
 // The display handles the DOM integration, both for input reading
 // and content drawing. It holds references to DOM nodes and
 // display-related state.
 
 function Display(place, doc, input) {
@@ -892,22 +897,22 @@ function findMaxLine(cm) {
       d.maxLine = line
     }
   })
 }
 
 // BIDI HELPERS
 
 function iterateBidiSections(order, from, to, f) {
-  if (!order) { return f(from, to, "ltr") }
+  if (!order) { return f(from, to, "ltr", 0) }
   var found = false
   for (var i = 0; i < order.length; ++i) {
     var part = order[i]
     if (part.from < to && part.to > from || from == to && part.to == from) {
-      f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr")
+      f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr", i)
       found = true
     }
   }
   if (!found) { f(from, to, "ltr") }
 }
 
 var bidiOther = null
 function getBidiPartAt(order, ch, sticky) {
@@ -1100,122 +1105,16 @@ var bidiOrdering = (function() {
 // false for lines that are fully left-to-right, and an array of
 // BidiSpan objects otherwise.
 function getOrder(line, direction) {
   var order = line.order
   if (order == null) { order = line.order = bidiOrdering(line.text, direction) }
   return order
 }
 
-function moveCharLogically(line, ch, dir) {
-  var target = skipExtendingChars(line.text, ch + dir, dir)
-  return target < 0 || target > line.text.length ? null : target
-}
-
-function moveLogically(line, start, dir) {
-  var ch = moveCharLogically(line, start.ch, dir)
-  return ch == null ? null : new Pos(start.line, ch, dir < 0 ? "after" : "before")
-}
-
-function endOfLine(visually, cm, lineObj, lineNo, dir) {
-  if (visually) {
-    var order = getOrder(lineObj, cm.doc.direction)
-    if (order) {
-      var part = dir < 0 ? lst(order) : order[0]
-      var moveInStorageOrder = (dir < 0) == (part.level == 1)
-      var sticky = moveInStorageOrder ? "after" : "before"
-      var ch
-      // With a wrapped rtl chunk (possibly spanning multiple bidi parts),
-      // it could be that the last bidi part is not on the last visual line,
-      // since visual lines contain content order-consecutive chunks.
-      // Thus, in rtl, we are looking for the first (content-order) character
-      // in the rtl chunk that is on the last line (that is, the same line
-      // as the last (content-order) character).
-      if (part.level > 0) {
-        var prep = prepareMeasureForLine(cm, lineObj)
-        ch = dir < 0 ? lineObj.text.length - 1 : 0
-        var targetTop = measureCharPrepared(cm, prep, ch).top
-        ch = findFirst(function (ch) { return measureCharPrepared(cm, prep, ch).top == targetTop; }, (dir < 0) == (part.level == 1) ? part.from : part.to - 1, ch)
-        if (sticky == "before") { ch = moveCharLogically(lineObj, ch, 1) }
-      } else { ch = dir < 0 ? part.to : part.from }
-      return new Pos(lineNo, ch, sticky)
-    }
-  }
-  return new Pos(lineNo, dir < 0 ? lineObj.text.length : 0, dir < 0 ? "before" : "after")
-}
-
-function moveVisually(cm, line, start, dir) {
-  var bidi = getOrder(line, cm.doc.direction)
-  if (!bidi) { return moveLogically(line, start, dir) }
-  if (start.ch >= line.text.length) {
-    start.ch = line.text.length
-    start.sticky = "before"
-  } else if (start.ch <= 0) {
-    start.ch = 0
-    start.sticky = "after"
-  }
-  var partPos = getBidiPartAt(bidi, start.ch, start.sticky), part = bidi[partPos]
-  if (cm.doc.direction == "ltr" && part.level % 2 == 0 && (dir > 0 ? part.to > start.ch : part.from < start.ch)) {
-    // Case 1: We move within an ltr part in an ltr editor. Even with wrapped lines,
-    // nothing interesting happens.
-    return moveLogically(line, start, dir)
-  }
-
-  var mv = function (pos, dir) { return moveCharLogically(line, pos instanceof Pos ? pos.ch : pos, dir); }
-  var prep
-  var getWrappedLineExtent = function (ch) {
-    if (!cm.options.lineWrapping) { return {begin: 0, end: line.text.length} }
-    prep = prep || prepareMeasureForLine(cm, line)
-    return wrappedLineExtentChar(cm, line, prep, ch)
-  }
-  var wrappedLineExtent = getWrappedLineExtent(start.sticky == "before" ? mv(start, -1) : start.ch)
-
-  if (cm.doc.direction == "rtl" || part.level == 1) {
-    var moveInStorageOrder = (part.level == 1) == (dir < 0)
-    var ch = mv(start, moveInStorageOrder ? 1 : -1)
-    if (ch != null && (!moveInStorageOrder ? ch >= part.from && ch >= wrappedLineExtent.begin : ch <= part.to && ch <= wrappedLineExtent.end)) {
-      // Case 2: We move within an rtl part or in an rtl editor on the same visual line
-      var sticky = moveInStorageOrder ? "before" : "after"
-      return new Pos(start.line, ch, sticky)
-    }
-  }
-
-  // Case 3: Could not move within this bidi part in this visual line, so leave
-  // the current bidi part
-
-  var searchInVisualLine = function (partPos, dir, wrappedLineExtent) {
-    var getRes = function (ch, moveInStorageOrder) { return moveInStorageOrder
-      ? new Pos(start.line, mv(ch, 1), "before")
-      : new Pos(start.line, ch, "after"); }
-
-    for (; partPos >= 0 && partPos < bidi.length; partPos += dir) {
-      var part = bidi[partPos]
-      var moveInStorageOrder = (dir > 0) == (part.level != 1)
-      var ch = moveInStorageOrder ? wrappedLineExtent.begin : mv(wrappedLineExtent.end, -1)
-      if (part.from <= ch && ch < part.to) { return getRes(ch, moveInStorageOrder) }
-      ch = moveInStorageOrder ? part.from : mv(part.to, -1)
-      if (wrappedLineExtent.begin <= ch && ch < wrappedLineExtent.end) { return getRes(ch, moveInStorageOrder) }
-    }
-  }
-
-  // Case 3a: Look for other bidi parts on the same visual line
-  var res = searchInVisualLine(partPos + dir, dir, wrappedLineExtent)
-  if (res) { return res }
-
-  // Case 3b: Look for other bidi parts on the next visual line
-  var nextCh = dir > 0 ? wrappedLineExtent.end : mv(wrappedLineExtent.begin, -1)
-  if (nextCh != null && !(dir > 0 && nextCh == line.text.length)) {
-    res = searchInVisualLine(dir > 0 ? 0 : bidi.length - 1, dir, getWrappedLineExtent(nextCh))
-    if (res) { return res }
-  }
-
-  // Case 4: Nowhere to move
-  return null
-}
-
 // EVENT HANDLING
 
 // Lightweight event framework. on/off also work on DOM nodes,
 // registering native DOM handlers.
 
 var noHandlers = []
 
 var on = function(emitter, type, f) {
@@ -2714,25 +2613,32 @@ function pageScrollX() {
   if (chrome && android) { return -(document.body.getBoundingClientRect().left - parseInt(getComputedStyle(document.body).marginLeft)) }
   return window.pageXOffset || (document.documentElement || document.body).scrollLeft
 }
 function pageScrollY() {
   if (chrome && android) { return -(document.body.getBoundingClientRect().top - parseInt(getComputedStyle(document.body).marginTop)) }
   return window.pageYOffset || (document.documentElement || document.body).scrollTop
 }
 
+function widgetTopHeight(lineObj) {
+  var height = 0
+  if (lineObj.widgets) { for (var i = 0; i < lineObj.widgets.length; ++i) { if (lineObj.widgets[i].above)
+    { height += widgetHeight(lineObj.widgets[i]) } } }
+  return height
+}
+
 // Converts a {top, bottom, left, right} box from line-local
 // coordinates into another coordinate system. Context may be one of
 // "line", "div" (display.lineDiv), "local"./null (editor), "window",
 // or "page".
 function intoCoordSystem(cm, lineObj, rect, context, includeWidgets) {
-  if (!includeWidgets && lineObj.widgets) { for (var i = 0; i < lineObj.widgets.length; ++i) { if (lineObj.widgets[i].above) {
-    var size = widgetHeight(lineObj.widgets[i])
-    rect.top += size; rect.bottom += size
-  } } }
+  if (!includeWidgets) {
+    var height = widgetTopHeight(lineObj)
+    rect.top += height; rect.bottom += height
+  }
   if (context == "line") { return rect }
   if (!context) { context = "local" }
   var yOff = heightAtLine(lineObj)
   if (context == "local") { yOff += paddingTop(cm.display) }
   else { yOff -= cm.display.viewOffset }
   if (context == "page" || context == "window") {
     var lOff = cm.display.lineSpace.getBoundingClientRect()
     yOff += lOff.top + (context == "window" ? 0 : pageScrollY())
@@ -2797,17 +2703,17 @@ function cursorCoords(cm, pos, context, 
     sticky = "before"
   } else if (ch <= 0) {
     ch = 0
     sticky = "after"
   }
   if (!order) { return get(sticky == "before" ? ch - 1 : ch, sticky == "before") }
 
   function getBidi(ch, partPos, invert) {
-    var part = order[partPos], right = (part.level % 2) != 0
+    var part = order[partPos], right = part.level == 1
     return get(invert ? ch - 1 : ch, right != invert)
   }
   var partPos = getBidiPartAt(order, ch, sticky)
   var other = bidiOther
   var val = getBidi(ch, partPos, sticky == "before")
   if (other != null) { val.other = getBidi(ch, other, sticky != "before") }
   return val
 }
@@ -2855,87 +2761,156 @@ function coordsChar(cm, x, y) {
     if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))
       { lineN = lineNo(lineObj = mergedPos.to.line) }
     else
       { return found }
   }
 }
 
 function wrappedLineExtent(cm, lineObj, preparedMeasure, y) {
-  var measure = function (ch) { return intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, ch), "line"); }
+  y -= widgetTopHeight(lineObj)
   var end = lineObj.text.length
-  var begin = findFirst(function (ch) { return measure(ch - 1).bottom <= y; }, end, 0)
-  end = findFirst(function (ch) { return measure(ch).top > y; }, begin, end)
+  var begin = findFirst(function (ch) { return measureCharPrepared(cm, preparedMeasure, ch - 1).bottom <= y; }, end, 0)
+  end = findFirst(function (ch) { return measureCharPrepared(cm, preparedMeasure, ch).top > y; }, begin, end)
   return {begin: begin, end: end}
 }
 
 function wrappedLineExtentChar(cm, lineObj, preparedMeasure, target) {
+  if (!preparedMeasure) { preparedMeasure = prepareMeasureForLine(cm, lineObj) }
   var targetTop = intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, target), "line").top
   return wrappedLineExtent(cm, lineObj, preparedMeasure, targetTop)
 }
 
+// Returns true if the given side of a box is after the given
+// coordinates, in top-to-bottom, left-to-right order.
+function boxIsAfter(box, x, y, left) {
+  return box.bottom <= y ? false : box.top > y ? true : (left ? box.left : box.right) > x
+}
+
 function coordsCharInner(cm, lineObj, lineNo, x, y) {
+  // Move y into line-local coordinate space
   y -= heightAtLine(lineObj)
-  var begin = 0, end = lineObj.text.length
   var preparedMeasure = prepareMeasureForLine(cm, lineObj)
-  var pos
+  // When directly calling `measureCharPrepared`, we have to adjust
+  // for the widgets at this line.
+  var widgetHeight = widgetTopHeight(lineObj)
+  var begin = 0, end = lineObj.text.length, ltr = true
+
   var order = getOrder(lineObj, cm.doc.direction)
+  // If the line isn't plain left-to-right text, first figure out
+  // which bidi section the coordinates fall into.
   if (order) {
-    if (cm.options.lineWrapping) {
-      ;var assign;
-      ((assign = wrappedLineExtent(cm, lineObj, preparedMeasure, y), begin = assign.begin, end = assign.end, assign))
-    }
-    pos = new Pos(lineNo, Math.floor(begin + (end - begin) / 2))
-    var beginLeft = cursorCoords(cm, pos, "line", lineObj, preparedMeasure).left
-    var dir = beginLeft < x ? 1 : -1
-    var prevDiff, diff = beginLeft - x, prevPos
-    var steps = Math.ceil((end - begin) / 4)
-    outer: do {
-      prevDiff = diff
-      prevPos = pos
-      var i = 0
-      for (; i < steps; ++i) {
-        var prevPos$1 = pos
-        pos = moveVisually(cm, lineObj, pos, dir)
-        if (pos == null || pos.ch < begin || end <= (pos.sticky == "before" ? pos.ch - 1 : pos.ch)) {
-          pos = prevPos$1
-          break outer
-        }
-      }
-      diff = cursorCoords(cm, pos, "line", lineObj, preparedMeasure).left - x
-      if (steps > 1) {
-        var diff_change_per_step = Math.abs(diff - prevDiff) / steps
-        steps = Math.min(steps, Math.ceil(Math.abs(diff) / diff_change_per_step))
-        dir = diff < 0 ? 1 : -1
-      }
-    } while (diff != 0 && (steps > 1 || ((dir < 0) != (diff < 0) && (Math.abs(diff) <= Math.abs(prevDiff)))))
-    if (Math.abs(diff) > Math.abs(prevDiff)) {
-      if ((diff < 0) == (prevDiff < 0)) { throw new Error("Broke out of infinite loop in coordsCharInner") }
-      pos = prevPos
-    }
+    var part = (cm.options.lineWrapping ? coordsBidiPartWrapped : coordsBidiPart)
+                 (cm, lineObj, lineNo, preparedMeasure, order, x, y)
+    ltr = part.level != 1
+    // The awkward -1 offsets are needed because findFirst (called
+    // on these below) will treat its first bound as inclusive,
+    // second as exclusive, but we want to actually address the
+    // characters in the part's range
+    begin = ltr ? part.from : part.to - 1
+    end = ltr ? part.to : part.from - 1
+  }
+
+  // A binary search to find the first character whose bounding box
+  // starts after the coordinates. If we run across any whose box wrap
+  // the coordinates, store that.
+  var chAround = null, boxAround = null
+  var ch = findFirst(function (ch) {
+    var box = measureCharPrepared(cm, preparedMeasure, ch)
+    box.top += widgetHeight; box.bottom += widgetHeight
+    if (!boxIsAfter(box, x, y, false)) { return false }
+    if (box.top <= y && box.left <= x) {
+      chAround = ch
+      boxAround = box
+    }
+    return true
+  }, begin, end)
+
+  var baseX, sticky, outside = false
+  // If a box around the coordinates was found, use that
+  if (boxAround) {
+    // Distinguish coordinates nearer to the left or right side of the box
+    var atLeft = x - boxAround.left < boxAround.right - x, atStart = atLeft == ltr
+    ch = chAround + (atStart ? 0 : 1)
+    sticky = atStart ? "after" : "before"
+    baseX = atLeft ? boxAround.left : boxAround.right
   } else {
-    var ch = findFirst(function (ch) {
-      var box = intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, ch), "line")
-      if (box.top > y) {
-        // For the cursor stickiness
-        end = Math.min(ch, end)
-        return true
-      }
-      else if (box.bottom <= y) { return false }
-      else if (box.left > x) { return true }
-      else if (box.right < x) { return false }
-      else { return (x - box.left < box.right - x) }
-    }, begin, end)
-    ch = skipExtendingChars(lineObj.text, ch, 1)
-    pos = new Pos(lineNo, ch, ch == end ? "before" : "after")
-  }
-  var coords = cursorCoords(cm, pos, "line", lineObj, preparedMeasure)
-  if (y < coords.top || coords.bottom < y) { pos.outside = true }
-  pos.xRel = x < coords.left ? -1 : (x > coords.right ? 1 : 0)
-  return pos
+    // (Adjust for extended bound, if necessary.)
+    if (!ltr && (ch == end || ch == begin)) { ch++ }
+    // To determine which side to associate with, get the box to the
+    // left of the character and compare it's vertical position to the
+    // coordinates
+    sticky = ch == 0 ? "after" : ch == lineObj.text.length ? "before" :
+      (measureCharPrepared(cm, preparedMeasure, ch - (ltr ? 1 : 0)).bottom + widgetHeight <= y) == ltr ?
+      "after" : "before"
+    // Now get accurate coordinates for this place, in order to get a
+    // base X position
+    var coords = cursorCoords(cm, Pos(lineNo, ch, sticky), "line", lineObj, preparedMeasure)
+    baseX = coords.left
+    outside = y < coords.top || y >= coords.bottom
+  }
+
+  ch = skipExtendingChars(lineObj.text, ch, 1)
+  return PosWithInfo(lineNo, ch, sticky, outside, x - baseX)
+}
+
+function coordsBidiPart(cm, lineObj, lineNo, preparedMeasure, order, x, y) {
+  // Bidi parts are sorted left-to-right, and in a non-line-wrapping
+  // situation, we can take this ordering to correspond to the visual
+  // ordering. This finds the first part whose end is after the given
+  // coordinates.
+  var index = findFirst(function (i) {
+    var part = order[i], ltr = part.level != 1
+    return boxIsAfter(cursorCoords(cm, Pos(lineNo, ltr ? part.to : part.from, ltr ? "before" : "after"),
+                                   "line", lineObj, preparedMeasure), x, y, true)
+  }, 0, order.length - 1)
+  var part = order[index]
+  // If this isn't the first part, the part's start is also after
+  // the coordinates, and the coordinates aren't on the same line as
+  // that start, move one part back.
+  if (index > 0) {
+    var ltr = part.level != 1
+    var start = cursorCoords(cm, Pos(lineNo, ltr ? part.from : part.to, ltr ? "after" : "before"),
+                             "line", lineObj, preparedMeasure)
+    if (boxIsAfter(start, x, y, true) && start.top > y)
+      { part = order[index - 1] }
+  }
+  return part
+}
+
+function coordsBidiPartWrapped(cm, lineObj, _lineNo, preparedMeasure, order, x, y) {
+  // In a wrapped line, rtl text on wrapping boundaries can do things
+  // that don't correspond to the ordering in our `order` array at
+  // all, so a binary search doesn't work, and we want to return a
+  // part that only spans one line so that the binary search in
+  // coordsCharInner is safe. As such, we first find the extent of the
+  // wrapped line, and then do a flat search in which we discard any
+  // spans that aren't on the line.
+  var ref = wrappedLineExtent(cm, lineObj, preparedMeasure, y);
+  var begin = ref.begin;
+  var end = ref.end;
+  var part = null, closestDist = null
+  for (var i = 0; i < order.length; i++) {
+    var p = order[i]
+    if (p.from >= end || p.to <= begin) { continue }
+    var ltr = p.level != 1
+    var endX = measureCharPrepared(cm, preparedMeasure, ltr ? Math.min(end, p.to) - 1 : Math.max(begin, p.from)).right
+    // Weigh against spans ending before this, so that they are only
+    // picked if nothing ends after
+    var dist = endX < x ? x - endX + 1e9 : endX - x
+    if (!part || closestDist > dist) {
+      part = p
+      closestDist = dist
+    }
+  }
+  if (!part) { part = order[order.length - 1] }
+  // Clip the part to the wrapped line.
+  if (part.from < begin) { part = {from: begin, to: part.to, level: part.level} }
+  if (part.to > end) { part = {from: part.from, to: end, level: part.level} }
+  return part
 }
 
 var measureText
 // Compute the default text height.
 function textHeight(display) {
   if (display.cachedTextHeight != null) { return display.cachedTextHeight }
   if (measureText == null) {
     measureText = elt("pre")
@@ -3051,22 +3026,24 @@ function findViewIndex(cm, n) {
   }
 }
 
 function updateSelection(cm) {
   cm.display.input.showSelection(cm.display.input.prepareSelection())
 }
 
 function prepareSelection(cm, primary) {
+  if ( primary === void 0 ) primary = true;
+
   var doc = cm.doc, result = {}
   var curFragment = result.cursors = document.createDocumentFragment()
   var selFragment = result.selection = document.createDocumentFragment()
 
   for (var i = 0; i < doc.sel.ranges.length; i++) {
-    if (primary === false && i == doc.sel.primIndex) { continue }
+    if (!primary && i == doc.sel.primIndex) { continue }
     var range = doc.sel.ranges[i]
     if (range.from().line >= cm.display.viewTo || range.to().line < cm.display.viewFrom) { continue }
     var collapsed = range.empty()
     if (collapsed || cm.options.showCursorWhenSelecting)
       { drawSelectionCursor(cm, range.head, curFragment) }
     if (!collapsed)
       { drawSelectionRange(cm, range, selFragment) }
   }
@@ -3087,16 +3064,18 @@ function drawSelectionCursor(cm, head, o
     var otherCursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor"))
     otherCursor.style.display = ""
     otherCursor.style.left = pos.other.left + "px"
     otherCursor.style.top = pos.other.top + "px"
     otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px"
   }
 }
 
+function cmpCoords(a, b) { return a.top - b.top || a.left - b.left }
+
 // Draws the given range as a highlighted selection
 function drawSelectionRange(cm, range, output) {
   var display = cm.display, doc = cm.doc
   var fragment = document.createDocumentFragment()
   var padding = paddingH(cm.display), leftSide = padding.left
   var rightSide = Math.max(display.sizerWidth, displayWidth(cm) - display.sizer.offsetLeft) - padding.right
 
   function add(left, top, width, bottom) {
@@ -3109,40 +3088,58 @@ function drawSelectionRange(cm, range, o
   function drawForLine(line, fromArg, toArg) {
     var lineObj = getLine(doc, line)
     var lineLen = lineObj.text.length
     var start, end
     function coords(ch, bias) {
       return charCoords(cm, Pos(line, ch), "div", lineObj, bias)
     }
 
-    iterateBidiSections(getOrder(lineObj, doc.direction), fromArg || 0, toArg == null ? lineLen : toArg, function (from, to, dir) {
-      var leftPos = coords(from, "left"), rightPos, left, right
-      if (from == to) {
-        rightPos = leftPos
-        left = right = leftPos.left
-      } else {
-        rightPos = coords(to - 1, "right")
-        if (dir == "rtl") { var tmp = leftPos; leftPos = rightPos; rightPos = tmp }
-        left = leftPos.left
-        right = rightPos.right
+    var order = getOrder(lineObj, doc.direction)
+    iterateBidiSections(order, fromArg || 0, toArg == null ? lineLen : toArg, function (from, to, dir, i) {
+      var fromPos = coords(from, dir == "ltr" ? "left" : "right")
+      var toPos = coords(to - 1, dir == "ltr" ? "right" : "left")
+      if (dir == "ltr") {
+        var fromLeft = fromArg == null && from == 0 ? leftSide : fromPos.left
+        var toRight = toArg == null && to == lineLen ? rightSide : toPos.right
+        if (toPos.top - fromPos.top <= 3) { // Single line
+          add(fromLeft, toPos.top, toRight - fromLeft, toPos.bottom)
+        } else { // Multiple lines
+          add(fromLeft, fromPos.top, null, fromPos.bottom)
+          if (fromPos.bottom < toPos.top) { add(leftSide, fromPos.bottom, null, toPos.top) }
+          add(leftSide, toPos.top, toPos.right, toPos.bottom)
+        }
+      } else if (from < to) { // RTL
+        var fromRight = fromArg == null && from == 0 ? rightSide : fromPos.right
+        var toLeft = toArg == null && to == lineLen ? leftSide : toPos.left
+        if (toPos.top - fromPos.top <= 3) { // Single line
+          add(toLeft, toPos.top, fromRight - toLeft, toPos.bottom)
+        } else { // Multiple lines
+          var topLeft = leftSide
+          if (i) {
+            var topEnd = wrappedLineExtentChar(cm, lineObj, null, from).end
+            // The coordinates returned for an RTL wrapped space tend to
+            // be complete bogus, so try to skip that here.
+            topLeft = coords(topEnd - (/\s/.test(lineObj.text.charAt(topEnd - 1)) ? 2 : 1), "left").left
+          }
+          add(topLeft, fromPos.top, fromRight - topLeft, fromPos.bottom)
+          if (fromPos.bottom < toPos.top) { add(leftSide, fromPos.bottom, null, toPos.top) }
+          var botWidth = null
+          if (i < order.length  - 1 || true) {
+            var botStart = wrappedLineExtentChar(cm, lineObj, null, to).begin
+            botWidth = coords(botStart, "right").right - toLeft
+          }
+          add(toLeft, toPos.top, botWidth, toPos.bottom)
+        }
       }
-      if (fromArg == null && from == 0) { left = leftSide }
-      if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part
-        add(left, leftPos.top, null, leftPos.bottom)
-        left = leftSide
-        if (leftPos.bottom < rightPos.top) { add(left, leftPos.bottom, null, rightPos.top) }
-      }
-      if (toArg == null && to == lineLen) { right = rightSide }
-      if (!start || leftPos.top < start.top || leftPos.top == start.top && leftPos.left < start.left)
-        { start = leftPos }
-      if (!end || rightPos.bottom > end.bottom || rightPos.bottom == end.bottom && rightPos.right > end.right)
-        { end = rightPos }
-      if (left < leftSide + 1) { left = leftSide }
-      add(left, rightPos.top, right - left, rightPos.bottom)
+
+      if (!start || cmpCoords(fromPos, start) < 0) { start = fromPos }
+      if (cmpCoords(toPos, start) < 0) { start = toPos }
+      if (!end || cmpCoords(fromPos, end) < 0) { end = fromPos }
+      if (cmpCoords(toPos, end) < 0) { end = toPos }
     })
     return {start: start, end: end}
   }
 
   var sFrom = range.from(), sTo = range.to()
   if (sFrom.line == sTo.line) {
     drawForLine(sFrom.line, sFrom.ch, sTo.ch)
   } else {
@@ -3762,30 +3759,30 @@ function endOperation_R2(op) {
     op.adjustWidthTo = measureChar(cm, display.maxLine, display.maxLine.text.length).left + 3
     cm.display.sizerWidth = op.adjustWidthTo
     op.barMeasure.scrollWidth =
       Math.max(display.scroller.clientWidth, display.sizer.offsetLeft + op.adjustWidthTo + scrollGap(cm) + cm.display.barWidth)
     op.maxScrollLeft = Math.max(0, display.sizer.offsetLeft + op.adjustWidthTo - displayWidth(cm))
   }
 
   if (op.updatedDisplay || op.selectionChanged)
-    { op.preparedSelection = display.input.prepareSelection(op.focus) }
+    { op.preparedSelection = display.input.prepareSelection() }
 }
 
 function endOperation_W2(op) {
   var cm = op.cm
 
   if (op.adjustWidthTo != null) {
     cm.display.sizer.style.minWidth = op.adjustWidthTo + "px"
     if (op.maxScrollLeft < cm.doc.scrollLeft)
       { setScrollLeft(cm, Math.min(cm.display.scroller.scrollLeft, op.maxScrollLeft), true) }
     cm.display.maxLineChanged = false
   }
 
-  var takeFocus = op.focus && op.focus == activeElt() && (!document.hasFocus || document.hasFocus())
+  var takeFocus = op.focus && op.focus == activeElt()
   if (op.preparedSelection)
     { cm.display.input.showSelection(op.preparedSelection, takeFocus) }
   if (op.updatedDisplay || op.startHeight != cm.doc.height)
     { updateScrollbars(cm, op.barMeasure) }
   if (op.updatedDisplay)
     { setDocumentHeight(cm, op.barMeasure) }
 
   if (op.selectionChanged) { restartBlink(cm) }
@@ -5364,17 +5361,18 @@ function makeChangeSingleDocInEditor(cm,
     if (changeHandler) { signalLater(cm, "change", cm, obj) }
     if (changesHandler) { (cm.curOp.changeObjs || (cm.curOp.changeObjs = [])).push(obj) }
   }
   cm.display.selForContextMenu = null
 }
 
 function replaceRange(doc, code, from, to, origin) {
   if (!to) { to = from }
-  if (cmp(to, from) < 0) { var tmp = to; to = from; from = tmp }
+  if (cmp(to, from) < 0) { var assign;
+    (assign = [to, from], from = assign[0], to = assign[1], assign) }
   if (typeof code == "string") { code = doc.splitLines(code) }
   makeChange(doc, {from: from, to: to, text: code, origin: origin})
 }
 
 // Rebasing/resetting history to deal with externally-sourced changes
 
 function rebaseHistSelSingle(pos, from, to, diff) {
   if (to < pos.line) {
@@ -6726,16 +6724,122 @@ function deleteNearSelection(cm, compute
   // Next, remove those actual ranges.
   runInOp(cm, function () {
     for (var i = kill.length - 1; i >= 0; i--)
       { replaceRange(cm.doc, "", kill[i].from, kill[i].to, "+delete") }
     ensureCursorVisible(cm)
   })
 }
 
+function moveCharLogically(line, ch, dir) {
+  var target = skipExtendingChars(line.text, ch + dir, dir)
+  return target < 0 || target > line.text.length ? null : target
+}
+
+function moveLogically(line, start, dir) {
+  var ch = moveCharLogically(line, start.ch, dir)
+  return ch == null ? null : new Pos(start.line, ch, dir < 0 ? "after" : "before")
+}
+
+function endOfLine(visually, cm, lineObj, lineNo, dir) {
+  if (visually) {
+    var order = getOrder(lineObj, cm.doc.direction)
+    if (order) {
+      var part = dir < 0 ? lst(order) : order[0]
+      var moveInStorageOrder = (dir < 0) == (part.level == 1)
+      var sticky = moveInStorageOrder ? "after" : "before"
+      var ch
+      // With a wrapped rtl chunk (possibly spanning multiple bidi parts),
+      // it could be that the last bidi part is not on the last visual line,
+      // since visual lines contain content order-consecutive chunks.
+      // Thus, in rtl, we are looking for the first (content-order) character
+      // in the rtl chunk that is on the last line (that is, the same line
+      // as the last (content-order) character).
+      if (part.level > 0) {
+        var prep = prepareMeasureForLine(cm, lineObj)
+        ch = dir < 0 ? lineObj.text.length - 1 : 0
+        var targetTop = measureCharPrepared(cm, prep, ch).top
+        ch = findFirst(function (ch) { return measureCharPrepared(cm, prep, ch).top == targetTop; }, (dir < 0) == (part.level == 1) ? part.from : part.to - 1, ch)
+        if (sticky == "before") { ch = moveCharLogically(lineObj, ch, 1) }
+      } else { ch = dir < 0 ? part.to : part.from }
+      return new Pos(lineNo, ch, sticky)
+    }
+  }
+  return new Pos(lineNo, dir < 0 ? lineObj.text.length : 0, dir < 0 ? "before" : "after")
+}
+
+function moveVisually(cm, line, start, dir) {
+  var bidi = getOrder(line, cm.doc.direction)
+  if (!bidi) { return moveLogically(line, start, dir) }
+  if (start.ch >= line.text.length) {
+    start.ch = line.text.length
+    start.sticky = "before"
+  } else if (start.ch <= 0) {
+    start.ch = 0
+    start.sticky = "after"
+  }
+  var partPos = getBidiPartAt(bidi, start.ch, start.sticky), part = bidi[partPos]
+  if (cm.doc.direction == "ltr" && part.level % 2 == 0 && (dir > 0 ? part.to > start.ch : part.from < start.ch)) {
+    // Case 1: We move within an ltr part in an ltr editor. Even with wrapped lines,
+    // nothing interesting happens.
+    return moveLogically(line, start, dir)
+  }
+
+  var mv = function (pos, dir) { return moveCharLogically(line, pos instanceof Pos ? pos.ch : pos, dir); }
+  var prep
+  var getWrappedLineExtent = function (ch) {
+    if (!cm.options.lineWrapping) { return {begin: 0, end: line.text.length} }
+    prep = prep || prepareMeasureForLine(cm, line)
+    return wrappedLineExtentChar(cm, line, prep, ch)
+  }
+  var wrappedLineExtent = getWrappedLineExtent(start.sticky == "before" ? mv(start, -1) : start.ch)
+
+  if (cm.doc.direction == "rtl" || part.level == 1) {
+    var moveInStorageOrder = (part.level == 1) == (dir < 0)
+    var ch = mv(start, moveInStorageOrder ? 1 : -1)
+    if (ch != null && (!moveInStorageOrder ? ch >= part.from && ch >= wrappedLineExtent.begin : ch <= part.to && ch <= wrappedLineExtent.end)) {
+      // Case 2: We move within an rtl part or in an rtl editor on the same visual line
+      var sticky = moveInStorageOrder ? "before" : "after"
+      return new Pos(start.line, ch, sticky)
+    }
+  }
+
+  // Case 3: Could not move within this bidi part in this visual line, so leave
+  // the current bidi part
+
+  var searchInVisualLine = function (partPos, dir, wrappedLineExtent) {
+    var getRes = function (ch, moveInStorageOrder) { return moveInStorageOrder
+      ? new Pos(start.line, mv(ch, 1), "before")
+      : new Pos(start.line, ch, "after"); }
+
+    for (; partPos >= 0 && partPos < bidi.length; partPos += dir) {
+      var part = bidi[partPos]
+      var moveInStorageOrder = (dir > 0) == (part.level != 1)
+      var ch = moveInStorageOrder ? wrappedLineExtent.begin : mv(wrappedLineExtent.end, -1)
+      if (part.from <= ch && ch < part.to) { return getRes(ch, moveInStorageOrder) }
+      ch = moveInStorageOrder ? part.from : mv(part.to, -1)
+      if (wrappedLineExtent.begin <= ch && ch < wrappedLineExtent.end) { return getRes(ch, moveInStorageOrder) }
+    }
+  }
+
+  // Case 3a: Look for other bidi parts on the same visual line
+  var res = searchInVisualLine(partPos + dir, dir, wrappedLineExtent)
+  if (res) { return res }
+
+  // Case 3b: Look for other bidi parts on the next visual line
+  var nextCh = dir > 0 ? wrappedLineExtent.end : mv(wrappedLineExtent.begin, -1)
+  if (nextCh != null && !(dir > 0 && nextCh == line.text.length)) {
+    res = searchInVisualLine(dir > 0 ? 0 : bidi.length - 1, dir, getWrappedLineExtent(nextCh))
+    if (res) { return res }
+  }
+
+  // Case 4: Nowhere to move
+  return null
+}
+
 // Commands are parameter-less actions that can be performed on an
 // editor, mostly used for keybindings.
 var commands = {
   selectAll: selectAll,
   singleSelection: function (cm) { return cm.setSelection(cm.getCursor("anchor"), cm.getCursor("head"), sel_dontScroll); },
   killLine: function (cm) { return deleteNearSelection(cm, function (range) {
     if (range.empty()) {
       var len = getLine(cm.doc, range.head.line).text.length
@@ -7287,17 +7391,17 @@ function leftButtonSelect(cm, event, sta
       if (cmp(range.anchor, anchor) > 0) {
         head = range.head
         anchor = minPos(oldRange.from(), range.anchor)
       } else {
         head = range.anchor
         anchor = maxPos(oldRange.to(), range.head)
       }
       var ranges$1 = startSel.ranges.slice(0)
-      ranges$1[ourIndex] = new Range(clipPos(doc, anchor), head)
+      ranges$1[ourIndex] = bidiSimplify(cm, new Range(clipPos(doc, anchor), head))
       setSelection(doc, normalizeSelection(ranges$1, ourIndex), sel_mouse)
     }
   }
 
   var editorSize = display.wrapper.getBoundingClientRect()
   // Used to ensure timeout re-tries don't fire when another extend
   // happened in the meantime (clearTimeout isn't reliable -- at
   // least on Chrome, the timeouts still happen even when cleared,
@@ -7339,23 +7443,62 @@ function leftButtonSelect(cm, event, sta
     else { extend(e) }
   })
   var up = operation(cm, done)
   cm.state.selectingText = up
   on(document, "mousemove", move)
   on(document, "mouseup", up)
 }
 
+// Used when mouse-selecting to adjust the anchor to the proper side
+// of a bidi jump depending on the visual position of the head.
+function bidiSimplify(cm, range) {
+  var anchor = range.anchor;
+  var head = range.head;
+  var anchorLine = getLine(cm.doc, anchor.line)
+  if (cmp(anchor, head) == 0 && anchor.sticky == head.sticky) { return range }
+  var order = getOrder(anchorLine)
+  if (!order) { return range }
+  var index = getBidiPartAt(order, anchor.ch, anchor.sticky), part = order[index]
+  if (part.from != anchor.ch && part.to != anchor.ch) { return range }
+  var boundary = index + ((part.from == anchor.ch) == (part.level != 1) ? 0 : 1)
+  if (boundary == 0 || boundary == order.length) { return range }
+
+  // Compute the relative visual position of the head compared to the
+  // anchor (<0 is to the left, >0 to the right)
+  var leftSide
+  if (head.line != anchor.line) {
+    leftSide = (head.line - anchor.line) * (cm.doc.direction == "ltr" ? 1 : -1) > 0
+  } else {
+    var headIndex = getBidiPartAt(order, head.ch, head.sticky)
+    var dir = headIndex - index || (head.ch - anchor.ch) * (part.level == 1 ? -1 : 1)
+    if (headIndex == boundary - 1 || headIndex == boundary)
+      { leftSide = dir < 0 }
+    else
+      { leftSide = dir > 0 }
+  }
+
+  var usePart = order[boundary + (leftSide ? -1 : 0)]
+  var from = leftSide == (usePart.level == 1)
+  var ch = from ? usePart.from : usePart.to, sticky = from ? "after" : "before"
+  return anchor.ch == ch && anchor.sticky == sticky ? range : new Range(new Pos(anchor.line, ch, sticky), head)
+}
+
 
 // Determines whether an event happened in the gutter, and fires the
 // handlers for the corresponding event.
 function gutterEvent(cm, e, type, prevent) {
   var mX, mY
-  try { mX = e.clientX; mY = e.clientY }
-  catch(e) { return false }
+  if (e.touches) {
+    mX = e.touches[0].clientX
+    mY = e.touches[0].clientY
+  } else {
+    try { mX = e.clientX; mY = e.clientY }
+    catch(e) { return false }
+  }
   if (mX >= Math.floor(cm.display.gutters.getBoundingClientRect().right)) { return false }
   if (prevent) { e_preventDefault(e) }
 
   var display = cm.display
   var lineBox = display.lineDiv.getBoundingClientRect()
 
   if (mY > lineBox.bottom || !hasHandler(cm, type)) { return e_defaultPrevented(e) }
   mY -= lineBox.top - display.viewOffset
@@ -7683,17 +7826,17 @@ function registerEventHandlers(cm) {
     return touch.radiusX <= 1 && touch.radiusY <= 1
   }
   function farAway(touch, other) {
     if (other.left == null) { return true }
     var dx = other.left - touch.left, dy = other.top - touch.top
     return dx * dx + dy * dy > 20 * 20
   }
   on(d.scroller, "touchstart", function (e) {
-    if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e)) {
+    if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e) && !clickInGutter(cm, e)) {
       d.input.ensurePolled()
       clearTimeout(touchFinished)
       var now = +new Date
       d.activeTouch = {start: now, moved: false,
                        prev: now - prevTouch.end <= 300 ? prevTouch : null}
       if (e.touches.length == 1) {
         d.activeTouch.left = e.touches[0].pageX
         d.activeTouch.top = e.touches[0].pageY
@@ -9467,13 +9610,13 @@ CodeMirror.defineExtension = function (n
 CodeMirror.defineDocExtension = function (name, func) {
   Doc.prototype[name] = func
 }
 
 CodeMirror.fromTextArea = fromTextArea
 
 addLegacyProps(CodeMirror)
 
-CodeMirror.version = "5.29.0"
+CodeMirror.version = "5.30.0"
 
 return CodeMirror;
 
 })));
\ No newline at end of file

--- a/devtools/client/sourceeditor/codemirror/mode/javascript/javascript.js
+++ b/devtools/client/sourceeditor/codemirror/mode/javascript/javascript.js
@@ -23,17 +23,17 @@ CodeMirror.defineMode("javascript", func
 
   var keywords = function(){
     function kw(type) {return {type: type, style: "keyword"};}
     var A = kw("keyword a"), B = kw("keyword b"), C = kw("keyword c");
     var operator = kw("operator"), atom = {type: "atom", style: "atom"};
 
     var jsKeywords = {
       "if": kw("if"), "while": A, "with": A, "else": B, "do": B, "try": B, "finally": B,
-      "return": C, "break": C, "continue": C, "new": kw("new"), "delete": C, "throw": C, "debugger": C,
+      "return": C, "break": C, "continue": C, "new": kw("new"), "delete": C, "void": C, "throw": C, "debugger": C,
       "var": kw("var"), "const": kw("var"), "let": kw("var"),
       "function": kw("function"), "catch": kw("catch"),
       "for": kw("for"), "switch": kw("switch"), "case": kw("case"), "default": kw("default"),
       "in": operator, "typeof": operator, "instanceof": operator,
       "true": atom, "false": atom, "null": atom, "undefined": atom, "NaN": atom, "Infinity": atom,
       "this": kw("this"), "class": kw("class"), "super": kw("atom"),
       "yield": C, "export": kw("export"), "import": kw("import"), "extends": C,
       "await": C
@@ -393,17 +393,17 @@ CodeMirror.defineMode("javascript", func
   }
   function parenExpr(type) {
     if (type != "(") return pass()
     return cont(pushlex(")"), expression, expect(")"), poplex)
   }
   function expressionInner(type, noComma) {
     if (cx.state.fatArrowAt == cx.stream.start) {
       var body = noComma ? arrowBodyNoComma : arrowBody;
-      if (type == "(") return cont(pushcontext, pushlex(")"), commasep(pattern, ")"), poplex, expect("=>"), body, popcontext);
+      if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, expect("=>"), body, popcontext);
       else if (type == "variable") return pass(pushcontext, pattern, expect("=>"), body, popcontext);
     }
 
     var maybeop = noComma ? maybeoperatorNoComma : maybeoperatorComma;
     if (atomicTypes.hasOwnProperty(type)) return cont(maybeop);
     if (type == "function") return cont(functiondef, maybeop);
     if (type == "class") return cont(pushlex("form"), classExpression, poplex);
     if (type == "keyword c" || type == "async") return cont(noComma ? maybeexpressionNoComma : maybeexpression);
@@ -438,16 +438,21 @@ CodeMirror.defineMode("javascript", func
       return cont(expr);
     }
     if (type == "quasi") { return pass(quasi, me); }
     if (type == ";") return;
     if (type == "(") return contCommasep(expressionNoComma, ")", "call", me);
     if (type == ".") return cont(property, me);
     if (type == "[") return cont(pushlex("]"), maybeexpression, expect("]"), poplex, me);
     if (isTS && value == "as") { cx.marked = "keyword"; return cont(typeexpr, me) }
+    if (type == "regexp") {
+      cx.state.lastType = cx.marked = "operator"
+      cx.stream.backUp(cx.stream.pos - cx.stream.start - 1)
+      return cont(expr)
+    }
   }
   function quasi(type, value) {
     if (type != "quasi") return pass();
     if (value.slice(value.length - 2) != "${") return cont(quasi);
     return cont(expression, continueQuasi);
   }
   function continueQuasi(type) {
     if (type == "}") {
@@ -486,16 +491,19 @@ CodeMirror.defineMode("javascript", func
   }
   function objprop(type, value) {
     if (type == "async") {
       cx.marked = "property";
       return cont(objprop);
     } else if (type == "variable" || cx.style == "keyword") {
       cx.marked = "property";
       if (value == "get" || value == "set") return cont(getterSetter);
+      var m // Work around fat-arrow-detection complication for detecting typescript typed arrow params
+      if (isTS && cx.state.fatArrowAt == cx.stream.start && (m = cx.stream.match(/^\s*:\s*/, false)))
+        cx.state.fatArrowAt = cx.stream.pos + m[0].length
       return cont(afterprop);
     } else if (type == "number" || type == "string") {
       cx.marked = jsonldMode ? "property" : (cx.style + " property");
       return cont(afterprop);
     } else if (type == "jsonld-keyword") {
       return cont(afterprop);
     } else if (type == "modifier") {
       return cont(objprop)
@@ -643,17 +651,18 @@ CodeMirror.defineMode("javascript", func
     if (type != ")") cont(expression);
   }
   function functiondef(type, value) {
     if (value == "*") {cx.marked = "keyword"; return cont(functiondef);}
     if (type == "variable") {register(value); return cont(functiondef);}
     if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, maybetype, statement, popcontext);
     if (isTS && value == "<") return cont(pushlex(">"), commasep(typeexpr, ">"), poplex, functiondef)
   }
-  function funarg(type) {
+  function funarg(type, value) {
+    if (value == "@") cont(expression, funarg)
     if (type == "spread" || type == "modifier") return cont(funarg);
     return pass(pattern, maybetype, maybeAssign);
   }
   function classExpression(type, value) {
     // Class expressions may have an optional name.
     if (type == "variable") return className(type, value);
     return classNameAfter(type, value);
   }
@@ -669,17 +678,17 @@ CodeMirror.defineMode("javascript", func
   function classBody(type, value) {
     if (type == "modifier" || type == "async" ||
         (type == "variable" &&
          (value == "static" || value == "get" || value == "set") &&
          cx.stream.match(/^\s+[\w$\xa1-\uffff]/, false))) {
       cx.marked = "keyword";
       return cont(classBody);
     }
-    if (type == "variable") {
+    if (type == "variable" || cx.style == "keyword") {
       cx.marked = "property";
       return cont(isTS ? classfield : functiondef, classBody);
     }
     if (type == "[")
       return cont(expression, expect("]"), isTS ? classfield : functiondef, classBody)
     if (value == "*") {
       cx.marked = "keyword";
       return cont(classBody);
@@ -731,17 +740,17 @@ CodeMirror.defineMode("javascript", func
   function isContinuedStatement(state, textAfter) {
     return state.lastType == "operator" || state.lastType == "," ||
       isOperatorChar.test(textAfter.charAt(0)) ||
       /[,.]/.test(textAfter.charAt(0));
   }
 
   function expressionAllowed(stream, state, backUp) {
     return state.tokenize == tokenBase &&
-      /^(?:operator|sof|keyword c|case|new|export|default|[\[{}\(,;:]|=>)$/.test(state.lastType) ||
+      /^(?:operator|sof|keyword [bc]|case|new|export|default|spread|[\[{}\(,;:]|=>)$/.test(state.lastType) ||
       (state.lastType == "quasi" && /\{\s*$/.test(stream.string.slice(0, stream.pos - (backUp || 0))))
   }
 
   // Interface
 
   return {
     startState: function(basecolumn) {
       var state = {

--- a/devtools/client/sourceeditor/test/codemirror/test.js
+++ b/devtools/client/sourceeditor/test/codemirror/test.js
@@ -249,16 +249,21 @@ testCM("coordsCharBidi", function(cm) {
         var coords = cm.charCoords(Pos(line, ch), sys);
         var pos = cm.coordsChar({left: coords.left + 1, top: coords.top + 1}, sys);
         eqCharPos(pos, Pos(line, ch));
       }
     }
   }
 }, {lineNumbers: true});
 
+testCM("badBidiOptimization", function(cm) {
+  var coords = cm.charCoords(Pos(0, 34))
+  eqCharPos(cm.coordsChar({left: coords.right, top: coords.top + 2}), Pos(0, 34))
+}, {value: "----------<p class=\"title\">هل يمكنك اختيار مستوى قسط التأمين الذي ترغب بدفعه؟</p>"})
+
 testCM("posFromIndex", function(cm) {
   cm.setValue(
     "This function should\n" +
     "convert a zero based index\n" +
     "to line and ch."
   );
 
   var examples = [
@@ -1151,16 +1156,26 @@ testCM("measureWrappedEndOfLine", functi
     if (i == 1) {
       var node = document.createElement("div");
       node.innerHTML = "hi"; node.style.height = "30px";
       cm.addLineWidget(0, node, {above: true});
     }
   }
 }, {mode: "text/html", value: "0123456789abcde0123456789", lineWrapping: true}, ie_lt8 || opera_lt10);
 
+testCM("measureEndOfLineBidi", function(cm) {
+  eqCursorPos(cm.coordsChar({left: 5000, top: cm.charCoords(Pos(0, 0)).top}), Pos(0, 8, "after"))
+}, {value: "إإإإuuuuإإإإ"})
+
+testCM("measureWrappedBidiLevel2", function(cm) {
+  cm.setSize(cm.charCoords(Pos(0, 6), "editor").right + 60)
+  var c9 = cm.charCoords(Pos(0, 9))
+  eqCharPos(cm.coordsChar({left: c9.right - 1, top: c9.top + 1}), Pos(0, 9))
+}, {value: "foobar إإ إإ إإ إإ 555 بببببب", lineWrapping: true})
+
 testCM("measureWrappedBeginOfLine", function(cm) {
   if (phantom) return;
   cm.setSize(null, "auto");
   var inner = byClassName(cm.getWrapperElement(), "CodeMirror-lines")[0].firstChild;
   var lh = inner.offsetHeight;
   for (var step = 10, w = cm.charCoords(Pos(0, 7), "div").right;; w += step) {
     cm.setSize(w);
     if (inner.offsetHeight < 2.5 * lh) {
@@ -2463,16 +2478,33 @@ function testCoordsWrappedBidi(str) {
 
 testCoordsWrappedBidi("Count ١ ٢ ٣ ٤");
 /*
 for (var i = 0; i < 5; ++i) {
   testCoordsWrappedBidi(getString(50));
 }
 */
 
+testCM("rtl_wrapped_selection", function(cm) {
+  cm.setSelection(Pos(0, 10), Pos(0, 190))
+  is(byClassName(cm.getWrapperElement(), "CodeMirror-selected").length >= 3)
+}, {value: new Array(10).join(" فتي تم تضمينها فتي تم"), lineWrapping: true})
+
+testCM("bidi_wrapped_selection", function(cm) {
+  if (phantom) return
+  cm.setSize(cm.charCoords(Pos(0, 10), "editor").left)
+  cm.setSelection(Pos(0, 37), Pos(0, 80))
+  var blocks = byClassName(cm.getWrapperElement(), "CodeMirror-selected")
+  is(blocks.length >= 2)
+  is(blocks.length <= 3)
+  var boxTop = blocks[0].getBoundingClientRect(), boxBot = blocks[blocks.length - 1].getBoundingClientRect()
+  is(boxTop.left > cm.charCoords(Pos(0, 1)).right)
+  is(boxBot.right < cm.charCoords(Pos(0, cm.getLine(0).length - 2)).left)
+}, {value: "<p>مفتي11 تم تضمينهفتي تم تضمينها فتي تفتي تم تضمينها فتي تفتي تم تضمينها فتي تفتي تم تضمينها فتي تا فت10ي ت</p>", lineWrapping: true})
+
 testCM("delete_wrapped", function(cm) {
   makeItWrapAfter(cm, Pos(0, 2));
   cm.doc.setCursor(Pos(0, 3, "after"));
   cm.deleteH(-1, "char");
   eq(cm.getLine(0), "1245");
 }, {value: "12345", lineWrapping: true})
 
 CodeMirror.defineMode("lookahead_mode", function() {

--- a/dom/base/ChildIterator.cpp
+++ b/dom/base/ChildIterator.cpp
@@ -3,17 +3,16 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "ChildIterator.h"
 #include "nsContentUtils.h"
 #include "mozilla/dom/XBLChildrenElement.h"
 #include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "nsIAnonymousContentCreator.h"
 #include "nsIFrame.h"
 #include "nsCSSAnonBoxes.h"
 
 namespace mozilla {
 namespace dom {
 
@@ -73,27 +72,16 @@ ExplicitChildIterator::GetNextChild()
     MOZ_ASSERT(!mDefaultChild);
 
     MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
     if (mIndexInInserted < assignedChildren.Length()) {
       return assignedChildren[mIndexInInserted++];
     }
     mIndexInInserted = 0;
     mChild = mChild->GetNextSibling();
-  } else if (mShadowIterator) {
-    // If we're inside of a <shadow> element, look through the
-    // explicit children of the projected ShadowRoot via
-    // the mShadowIterator.
-    nsIContent* nextChild = mShadowIterator->GetNextChild();
-    if (nextChild) {
-      return nextChild;
-    }
-
-    mShadowIterator = nullptr;
-    mChild = mChild->GetNextSibling();
   } else if (mDefaultChild) {
     // If we're already in default content, check if there are more nodes there
     MOZ_ASSERT(mChild);
     MOZ_ASSERT(nsContentUtils::IsContentInsertionPoint(mChild));
 
     mDefaultChild = mDefaultChild->GetNextSibling();
     if (mDefaultChild) {
       return mDefaultChild;
@@ -105,33 +93,17 @@ ExplicitChildIterator::GetNextChild()
     mIsFirst = false;
   } else if (mChild) { // in the middle of the child list
     mChild = mChild->GetNextSibling();
   }
 
   // Iterate until we find a non-insertion point, or an insertion point with
   // content.
   while (mChild) {
-    // If the current child being iterated is a shadow insertion point then
-    // the iterator needs to go into the projected ShadowRoot.
-    if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
-      // Look for the next child in the projected ShadowRoot for the <shadow>
-      // element.
-      HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
-      ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
-      if (projectedShadow) {
-        mShadowIterator = new ExplicitChildIterator(projectedShadow);
-        nsIContent* nextChild = mShadowIterator->GetNextChild();
-        if (nextChild) {
-          return nextChild;
-        }
-        mShadowIterator = nullptr;
-      }
-      mChild = mChild->GetNextSibling();
-    } else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
+    if (nsContentUtils::IsContentInsertionPoint(mChild)) {
       // If the current child being iterated is a content insertion point
       // then the iterator needs to return the nodes distributed into
       // the content insertion point.
       MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
       if (!assignedChildren.IsEmpty()) {
         // Iterate through elements projected on insertion point.
         mIndexInInserted = 1;
         return assignedChildren[0];
@@ -191,21 +163,19 @@ FlattenedChildIterator::Init(bool aIgnor
 
 bool
 ExplicitChildIterator::Seek(nsIContent* aChildToFind)
 {
   if (aChildToFind->GetParent() == mParent &&
       !aChildToFind->IsRootOfAnonymousSubtree()) {
     // Fast path: just point ourselves to aChildToFind, which is a
     // normal DOM child of ours.
-    MOZ_ASSERT(!ShadowRoot::IsShadowInsertionPoint(aChildToFind));
     MOZ_ASSERT(!nsContentUtils::IsContentInsertionPoint(aChildToFind));
     mChild = aChildToFind;
     mIndexInInserted = 0;
-    mShadowIterator = nullptr;
     mDefaultChild = nullptr;
     mIsFirst = false;
     return true;
   }
 
   // Can we add more fast paths here based on whether the parent of aChildToFind
   // is a shadow insertion point or content insertion point?
 
@@ -216,41 +186,33 @@ ExplicitChildIterator::Seek(nsIContent* 
 nsIContent*
 ExplicitChildIterator::Get() const
 {
   MOZ_ASSERT(!mIsFirst);
 
   if (mIndexInInserted) {
     MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
     return assignedChildren[mIndexInInserted - 1];
-  } else if (mShadowIterator)  {
-    return mShadowIterator->Get();
   }
+
   return mDefaultChild ? mDefaultChild : mChild;
 }
 
 nsIContent*
 ExplicitChildIterator::GetPreviousChild()
 {
   // If we're already in the inserted-children array, look there first
   if (mIndexInInserted) {
     // NB: mIndexInInserted points one past the last returned child so we need
     // to look *two* indices back in order to return the previous child.
     MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
     if (--mIndexInInserted) {
       return assignedChildren[mIndexInInserted - 1];
     }
     mChild = mChild->GetPreviousSibling();
-  } else if (mShadowIterator) {
-    nsIContent* previousChild = mShadowIterator->GetPreviousChild();
-    if (previousChild) {
-      return previousChild;
-    }
-    mShadowIterator = nullptr;
-    mChild = mChild->GetPreviousSibling();
   } else if (mDefaultChild) {
     // If we're already in default content, check if there are more nodes there
     mDefaultChild = mDefaultChild->GetPreviousSibling();
     if (mDefaultChild) {
       return mDefaultChild;
     }
 
     mChild = mChild->GetPreviousSibling();
@@ -260,32 +222,17 @@ ExplicitChildIterator::GetPreviousChild(
     mChild = mChild->GetPreviousSibling();
   } else { // at the end of the child list
     mChild = mParent->GetLastChild();
   }
 
   // Iterate until we find a non-insertion point, or an insertion point with
   // content.
   while (mChild) {
-    if (ShadowRoot::IsShadowInsertionPoint(mChild)) {
-      // If the current child being iterated is a shadow insertion point then
-      // the iterator needs to go into the projected ShadowRoot.
-      HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(mChild);
-      ShadowRoot* projectedShadow = shadowElem->GetOlderShadowRoot();
-      if (projectedShadow) {
-        // Create a ExplicitChildIterator that begins iterating from the end.
-        mShadowIterator = new ExplicitChildIterator(projectedShadow, false);
-        nsIContent* previousChild = mShadowIterator->GetPreviousChild();
-        if (previousChild) {
-          return previousChild;
-        }
-        mShadowIterator = nullptr;
-      }
-      mChild = mChild->GetPreviousSibling();
-    } else if (nsContentUtils::IsContentInsertionPoint(mChild)) {
+    if (nsContentUtils::IsContentInsertionPoint(mChild)) {
       // If the current child being iterated is a content insertion point
       // then the iterator needs to return the nodes distributed into
       // the content insertion point.
       MatchedNodes assignedChildren = GetMatchedNodesForPoint(mChild);
       if (!assignedChildren.IsEmpty()) {
         mIndexInInserted = assignedChildren.Length();
         return assignedChildren[mIndexInInserted - 1];
       }

--- a/dom/base/ChildIterator.h
+++ b/dom/base/ChildIterator.h
@@ -43,26 +43,22 @@ public:
       mIsFirst(aStartAtBeginning),
       mIndexInInserted(0)
   {
   }
 
   ExplicitChildIterator(const ExplicitChildIterator& aOther)
     : mParent(aOther.mParent), mChild(aOther.mChild),
       mDefaultChild(aOther.mDefaultChild),
-      mShadowIterator(aOther.mShadowIterator ?
-                      new ExplicitChildIterator(*aOther.mShadowIterator) :
-                      nullptr),
       mIsFirst(aOther.mIsFirst),
       mIndexInInserted(aOther.mIndexInInserted) {}
 
   ExplicitChildIterator(ExplicitChildIterator&& aOther)
     : mParent(aOther.mParent), mChild(aOther.mChild),
       mDefaultChild(aOther.mDefaultChild),
-      mShadowIterator(Move(aOther.mShadowIterator)),
       mIsFirst(aOther.mIsFirst),
       mIndexInInserted(aOther.mIndexInInserted) {}
 
   nsIContent* GetNextChild();
 
   // Looks for aChildToFind respecting insertion points until aChildToFind is
   // found.  This version can take shortcuts that the two-argument version
   // can't, so can be faster (and in fact can be O(1) instead of O(N) in many
@@ -111,21 +107,16 @@ protected:
   nsIContent* mChild;
 
   // If non-null, this points to the current default content for the current
   // insertion point that we're iterating (i.e. mChild, which must be an
   // nsXBLChildrenElement or HTMLContentElement). Once this transitions back
   // to null, we continue iterating at mChild's next sibling.
   nsIContent* mDefaultChild;
 
-  // If non-null, this points to an iterator of the explicit children of
-  // the ShadowRoot projected by the current shadow element that we're
-  // iterating.
-  nsAutoPtr<ExplicitChildIterator> mShadowIterator;
-
   // A flag to let us know that we haven't started iterating yet.
   bool mIsFirst;
 
   // If not zero, we're iterating inserted children for an insertion point. This
   // is an index into mChild's inserted children array (mChild must be an
   // nsXBLChildrenElement). The index is one past the "current" child (as
   // opposed to mChild which represents the "current" child).
   uint32_t mIndexInInserted;

--- a/dom/base/CustomElementRegistry.cpp
+++ b/dom/base/CustomElementRegistry.cpp
@@ -934,17 +934,17 @@ DoUpgrade(Element* aElement,
     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
     return;
   }
 }
 
 } // anonymous namespace
 
 // https://html.spec.whatwg.org/multipage/scripting.html#upgrades
-void
+/* static */ void
 CustomElementRegistry::Upgrade(Element* aElement,
                                CustomElementDefinition* aDefinition,
                                ErrorResult& aRv)
 {
   aElement->RemoveStates(NS_EVENT_STATE_UNRESOLVED);
 
   RefPtr<CustomElementData> data = aElement->GetCustomElementData();
   MOZ_ASSERT(data, "CustomElementData should exist");
@@ -972,18 +972,20 @@ CustomElementRegistry::Upgrade(Element* 
                                                             namespaceURI);
 
         LifecycleCallbackArgs args = {
           nsDependentAtomString(attrName),
           VoidString(),
           (attrValue.IsEmpty() ? VoidString() : attrValue),
           (namespaceURI.IsEmpty() ? VoidString() : namespaceURI)
         };
-        EnqueueLifecycleCallback(nsIDocument::eAttributeChanged, aElement,
-                                 &args, aDefinition);
+        nsContentUtils::EnqueueLifecycleCallback(aElement->OwnerDoc(),
+                                                 nsIDocument::eAttributeChanged,
+                                                 aElement,
+                                                 &args, aDefinition);
       }
     }
   }
 
   // Step 4.
   // TODO: Bug 1334043 - Implement connected lifecycle callbacks for custom elements
 
   // Step 5.
@@ -998,17 +1000,19 @@ CustomElementRegistry::Upgrade(Element* 
     data->mReactionQueue.Clear();
     return;
   }
 
   // Step 8.
   data->mState = CustomElementData::State::eCustom;
 
   // This is for old spec.
-  EnqueueLifecycleCallback(nsIDocument::eCreated, aElement, nullptr, aDefinition);
+  nsContentUtils::EnqueueLifecycleCallback(aElement->OwnerDoc(),
+                                           nsIDocument::eCreated,
+                                           aElement, nullptr, aDefinition);
 }
 
 //-----------------------------------------------------
 // CustomElementReactionsStack
 
 void
 CustomElementReactionsStack::CreateAndPushElementQueue()
 {

--- a/dom/base/CustomElementRegistry.h
+++ b/dom/base/CustomElementRegistry.h
@@ -357,32 +357,33 @@ public:
   void EnqueueLifecycleCallback(nsIDocument::ElementCallbackType aType,
                                 Element* aCustomElement,
                                 LifecycleCallbackArgs* aArgs,
                                 CustomElementDefinition* aDefinition);
 
   void GetCustomPrototype(nsIAtom* aAtom,
                           JS::MutableHandle<JSObject*> aPrototype);
 
+  void SyncInvokeReactions(nsIDocument::ElementCallbackType aType,
+                           Element* aCustomElement,
+                           CustomElementDefinition* aDefinition);
+
   /**
    * Upgrade an element.
    * https://html.spec.whatwg.org/multipage/scripting.html#upgrades
    */
-  void Upgrade(Element* aElement, CustomElementDefinition* aDefinition, ErrorResult& aRv);
+  static void Upgrade(Element* aElement, CustomElementDefinition* aDefinition, ErrorResult& aRv);
 
 private:
   ~CustomElementRegistry();
 
   UniquePtr<CustomElementCallback> CreateCustomElementCallback(
     nsIDocument::ElementCallbackType aType, Element* aCustomElement,
     LifecycleCallbackArgs* aArgs, CustomElementDefinition* aDefinition);
 
-  void SyncInvokeReactions(nsIDocument::ElementCallbackType aType,
-                           Element* aCustomElement,
-                           CustomElementDefinition* aDefinition);
   /**
    * Registers an unresolved custom element that is a candidate for
    * upgrade when the definition is registered via registerElement.
    * |aTypeName| is the name of the custom element type, if it is not
    * provided, then element name is used. |aTypeName| should be provided
    * when registering a custom element that extends an existing
    * element. e.g. <button is="x-button">.
    */

--- a/dom/base/DocumentFragment.cpp
+++ b/dom/base/DocumentFragment.cpp
@@ -106,19 +106,17 @@ DocumentFragment::Constructor(const Glob
   if (!window || !window->GetDoc()) {
     aRv.Throw(NS_ERROR_FAILURE);
     return nullptr;
   }
 
   return window->GetDoc()->CreateDocumentFragment();
 }
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(DocumentFragment,
-                                   FragmentOrElement,
-                                   mHost)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(DocumentFragment, FragmentOrElement, mHost)
 
 // QueryInterface implementation for DocumentFragment
 NS_INTERFACE_MAP_BEGIN(DocumentFragment)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(DocumentFragment)
   NS_INTERFACE_MAP_ENTRY(nsIContent)
   NS_INTERFACE_MAP_ENTRY(nsINode)
   NS_INTERFACE_MAP_ENTRY(nsIDOMDocumentFragment)

--- a/dom/base/DocumentFragment.h
+++ b/dom/base/DocumentFragment.h
@@ -38,18 +38,17 @@ public:
   using FragmentOrElement::GetFirstChild;
   using nsINode::QuerySelector;
   using nsINode::QuerySelectorAll;
   // Make sure bindings can see our superclass' protected GetElementById method.
   using nsINode::GetElementById;
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocumentFragment,
-                                           FragmentOrElement)
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocumentFragment, FragmentOrElement)
 
   // interface nsIDOMNode
   NS_FORWARD_NSIDOMNODE_TO_NSINODE
 
   // interface nsIDOMDocumentFragment
   NS_DECL_NSIDOMDOCUMENTFRAGMENT
 
   explicit DocumentFragment(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
@@ -117,25 +116,19 @@ public:
     NS_ASSERTION(false, "Trying to unbind a fragment from a tree");
   }
 
   virtual Element* GetNameSpaceElement() override
   {
     return nullptr;
   }
 
-  Element* GetHost() const
-  {
-    return mHost;
-  }
+  Element* GetHost() const { return mHost; }
 
-  void SetHost(Element* aHost)
-  {
-    mHost = aHost;
-  }
+  void SetHost(Element* aHost) { mHost = aHost; }
 
   static already_AddRefed<DocumentFragment>
   Constructor(const GlobalObject& aGlobal, ErrorResult& aRv);
 
 #ifdef DEBUG
   virtual void List(FILE* out, int32_t aIndent) const override;
   virtual void DumpContent(FILE* out, int32_t aIndent, bool aDumpAll) const override;
 #endif

--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1101,16 +1101,21 @@ Element::RemoveFromIdTable()
       doc->RemoveFromIdTable(this, id);
     }
   }
 }
 
 already_AddRefed<ShadowRoot>
 Element::CreateShadowRoot(ErrorResult& aError)
 {
+  if (GetShadowRoot()) {
+    aError.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+
   nsAutoScriptBlocker scriptBlocker;
 
   RefPtr<mozilla::dom::NodeInfo> nodeInfo;
   nodeInfo = mNodeInfo->NodeInfoManager()->GetNodeInfo(
     nsGkAtoms::documentFragmentNodeName, nullptr, kNameSpaceID_None,
     nsIDOMNode::DOCUMENT_FRAGMENT_NODE);
 
   RefPtr<nsXBLDocumentInfo> docInfo = new nsXBLDocumentInfo(OwnerDoc());
@@ -1137,34 +1142,17 @@ Element::CreateShadowRoot(ErrorResult& a
   // Calling SetPrototypeBinding takes ownership of protoBinding.
   docInfo->SetPrototypeBinding(NS_LITERAL_CSTRING("shadowroot"), protoBinding);
 
   RefPtr<ShadowRoot> shadowRoot = new ShadowRoot(this, nodeInfo.forget(),
                                                    protoBinding);
 
   shadowRoot->SetIsComposedDocParticipant(IsInComposedDoc());
 
-  // Replace the old ShadowRoot with the new one and let the old
-  // ShadowRoot know about the younger ShadowRoot because the old
-  // ShadowRoot is projected into the younger ShadowRoot's shadow
-  // insertion point (if it exists).
-  ShadowRoot* olderShadow = GetShadowRoot();
   SetShadowRoot(shadowRoot);
-  if (olderShadow) {
-    olderShadow->SetYoungerShadow(shadowRoot);
-
-    // Unbind children of older shadow root because they
-    // are no longer in the composed tree.
-    for (nsIContent* child = olderShadow->GetFirstChild(); child;
-         child = child->GetNextSibling()) {
-      child->UnbindFromTree(true, false);
-    }
-
-    olderShadow->SetIsComposedDocParticipant(false);
-  }
 
   // xblBinding takes ownership of docInfo.
   RefPtr<nsXBLBinding> xblBinding = new nsXBLBinding(shadowRoot, protoBinding);
   shadowRoot->SetAssociatedBinding(xblBinding);
   xblBinding->SetBoundElement(this);
 
   SetXBLBinding(xblBinding);
   return shadowRoot.forget();

--- a/dom/base/FragmentOrElement.cpp
+++ b/dom/base/FragmentOrElement.cpp
@@ -1042,33 +1042,20 @@ nsIContent::GetEventTargetParent(EventCh
   }
 
   nsIContent* parent = GetParent();
 
   // Web components have a special event chain that need to account
   // for destination insertion points where nodes have been distributed.
   nsTArray<nsIContent*>* destPoints = GetExistingDestInsertionPoints();
   if (destPoints && !destPoints->IsEmpty()) {
-    // Push destination insertion points to aVisitor.mDestInsertionPoints
-    // excluding shadow insertion points.
-    bool didPushNonShadowInsertionPoint = false;
+    // Push destination insertion points to aVisitor.mDestInsertionPoints.
     for (uint32_t i = 0; i < destPoints->Length(); i++) {
       nsIContent* point = destPoints->ElementAt(i);
-      if (!ShadowRoot::IsShadowInsertionPoint(point)) {
-        aVisitor.mDestInsertionPoints.AppendElement(point);
-        didPushNonShadowInsertionPoint = true;
-      }
-    }
-
-    // Next node in the event path is the final destination
-    // (non-shadow) insertion point that was pushed.
-    if (didPushNonShadowInsertionPoint) {
-      parent = aVisitor.mDestInsertionPoints.LastElement();
-      aVisitor.mDestInsertionPoints.SetLength(
-        aVisitor.mDestInsertionPoints.Length() - 1);
+      aVisitor.mDestInsertionPoints.AppendElement(point);
     }
   }
 
   ShadowRoot* thisShadowRoot = ShadowRoot::FromNode(this);
   if (thisShadowRoot) {
     if (!aVisitor.mEvent->mFlags.mComposed) {
       // If we do stop propagation, we still want to propagate
       // the event to chrome (nsPIDOMWindow::GetParentTarget()).
@@ -1082,20 +1069,17 @@ nsIContent::GetEventTargetParent(EventCh
       return NS_OK;
     }
 
     if (!aVisitor.mDestInsertionPoints.IsEmpty()) {
       parent = aVisitor.mDestInsertionPoints.LastElement();
       aVisitor.mDestInsertionPoints.SetLength(
         aVisitor.mDestInsertionPoints.Length() - 1);
     } else {
-      // The pool host for the youngest shadow root is shadow DOM host,
-      // for older shadow roots, it is the shadow insertion point
-      // where the shadow root is projected, nullptr if none exists.
-      parent = thisShadowRoot->GetPoolHost();
+      parent = thisShadowRoot->GetHost();
     }
   }
 
   // Event may need to be retargeted if this is the root of a native
   // anonymous content subtree or event is dispatched somewhere inside XBL.
   if (isAnonForEvents) {
 #ifdef DEBUG
     // If a DOM event is explicitly dispatched using node.dispatchEvent(), then
@@ -2614,13 +2598,12 @@ FragmentOrElement::SetIsElementInStyleSc
 }
 
 void
 FragmentOrElement::SetIsElementInStyleScopeFlagOnShadowTree(bool aInStyleScope)
 {
   NS_ASSERTION(IsElement(), "calling SetIsElementInStyleScopeFlagOnShadowTree "
                             "on a non-Element is useless");
   ShadowRoot* shadowRoot = GetShadowRoot();
-  while (shadowRoot) {
+  if (shadowRoot) {
     shadowRoot->SetIsElementInStyleScopeFlagOnSubtree(aInStyleScope);
-    shadowRoot = shadowRoot->GetOlderShadowRoot();
   }
 }

--- a/dom/base/ShadowRoot.cpp
+++ b/dom/base/ShadowRoot.cpp
@@ -10,99 +10,90 @@
 #include "mozilla/dom/DocumentFragment.h"
 #include "ChildIterator.h"
 #include "nsContentUtils.h"
 #include "nsDOMClassInfoID.h"
 #include "nsIDOMHTMLElement.h"
 #include "nsIStyleSheetLinkingElement.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "nsXBLPrototypeBinding.h"
 #include "mozilla/StyleSheet.h"
 #include "mozilla/StyleSheetInlines.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(ShadowRoot)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ShadowRoot,
                                                   DocumentFragment)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPoolHost)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStyleSheetList)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOlderShadow)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mYoungerShadow)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAssociatedBinding)
   for (auto iter = tmp->mIdentifierMap.ConstIter(); !iter.Done();
        iter.Next()) {
     iter.Get()->Traverse(&cb);
   }
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(ShadowRoot,
-                                                DocumentFragment)
-  if (tmp->mPoolHost) {
-    tmp->mPoolHost->RemoveMutationObserver(tmp);
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ShadowRoot)
+  if (tmp->GetHost()) {
+    tmp->GetHost()->RemoveMutationObserver(tmp);
   }
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPoolHost)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mStyleSheetList)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mOlderShadow)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mYoungerShadow)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mAssociatedBinding)
   tmp->mIdentifierMap.Clear();
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(DocumentFragment)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ShadowRoot)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIContent)
   NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
 NS_INTERFACE_MAP_END_INHERITING(DocumentFragment)
 
 NS_IMPL_ADDREF_INHERITED(ShadowRoot, DocumentFragment)
 NS_IMPL_RELEASE_INHERITED(ShadowRoot, DocumentFragment)
 
 ShadowRoot::ShadowRoot(Element* aElement,
                        already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
                        nsXBLPrototypeBinding* aProtoBinding)
-  : DocumentFragment(aNodeInfo), mPoolHost(aElement),
-    mProtoBinding(aProtoBinding), mShadowElement(nullptr),
-    mInsertionPointChanged(false), mIsComposedDocParticipant(false)
+  : DocumentFragment(aNodeInfo)
+  , mProtoBinding(aProtoBinding)
+  , mInsertionPointChanged(false)
+  , mIsComposedDocParticipant(false)
 {
   SetHost(aElement);
 
   // Nodes in a shadow tree should never store a value
   // in the subtree root pointer, nodes in the shadow tree
   // track the subtree root using GetContainingShadow().
   ClearSubtreeRootPointer();
 
   SetFlags(NODE_IS_IN_SHADOW_TREE);
 
   ExtendedDOMSlots()->mBindingParent = aElement;
   ExtendedDOMSlots()->mContainingShadow = this;
 
   // Add the ShadowRoot as a mutation observer on the host to watch
   // for mutations because the insertion points in this ShadowRoot
   // may need to be updated when the host children are modified.
-  mPoolHost->AddMutationObserver(this);
+  GetHost()->AddMutationObserver(this);
 }
 
 ShadowRoot::~ShadowRoot()
 {
-  if (mPoolHost) {
+  if (GetHost()) {
     // mPoolHost may have been unlinked or a new ShadowRoot may have been
     // creating, making this one obsolete.
-    mPoolHost->RemoveMutationObserver(this);
+    GetHost()->RemoveMutationObserver(this);
   }
 
   UnsetFlags(NODE_IS_IN_SHADOW_TREE);
 
   // nsINode destructor expects mSubtreeRoot == this.
   SetSubtreeRootPointer(this);
-
-  SetHost(nullptr);
 }
 
 JSObject*
 ShadowRoot::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
   return mozilla::dom::ShadowRootBinding::Wrap(aCx, this, aGivenProto);
 }
 
@@ -239,25 +230,16 @@ ShadowRoot::AddInsertionPoint(HTMLConten
 
 void
 ShadowRoot::RemoveInsertionPoint(HTMLContentElement* aInsertionPoint)
 {
   mInsertionPoints.RemoveElement(aInsertionPoint);
 }
 
 void
-ShadowRoot::SetYoungerShadow(ShadowRoot* aYoungerShadow)
-{
-  mYoungerShadow = aYoungerShadow;
-  mYoungerShadow->mOlderShadow = this;
-
-  ChangePoolHost(mYoungerShadow->GetShadowElement());
-}
-
-void
 ShadowRoot::RemoveDestInsertionPoint(nsIContent* aInsertionPoint,
                                      nsTArray<nsIContent*>& aDestInsertionPoints)
 {
   // Remove the insertion point from the destination insertion points.
   // Also remove all succeeding insertion points because it is no longer
   // possible for the content to be distributed into deeper node trees.
   int32_t index = aDestInsertionPoints.IndexOf(aInsertionPoint);
 
@@ -295,18 +277,17 @@ ShadowRoot::DistributeSingleNode(nsICont
   }
 
   // Find the index into the insertion point.
   if (insertionPoint) {
     nsCOMArray<nsIContent>& matchedNodes = insertionPoint->MatchedNodes();
     // Find the appropriate position in the matched node list for the
     // newly distributed content.
     bool isIndexFound = false;
-    MOZ_ASSERT(mPoolHost, "Where did the content come from if there is no pool host?");
-    ExplicitChildIterator childIterator(mPoolHost);
+    ExplicitChildIterator childIterator(GetHost());
     for (uint32_t i = 0; i < matchedNodes.Length(); i++) {
       // Seek through the host's explicit children until the inserted content
       // is found or when the current matched node is reached.
       if (childIterator.Seek(aContent, matchedNodes[i])) {
         // aContent was found before the current matched node.
         insertionPoint->InsertMatchedNode(i, aContent);
         isIndexFound = true;
         break;
@@ -316,42 +297,23 @@ ShadowRoot::DistributeSingleNode(nsICont
     if (!isIndexFound) {
       // We have still not found an index in the insertion point,
       // thus it must be at the end.
       MOZ_ASSERT(childIterator.Seek(aContent, nullptr),
                  "Trying to match a node that is not a candidate to be matched");
       insertionPoint->AppendMatchedNode(aContent);
     }
 
-    // Handle the case where the parent of the insertion point is a ShadowRoot
-    // that is projected into the younger ShadowRoot's shadow insertion point.
-    // The node distributed into the insertion point must be reprojected
-    // to the shadow insertion point.
-    if (insertionPoint->GetParent() == this &&
-        mYoungerShadow && mYoungerShadow->GetShadowElement()) {
-      mYoungerShadow->GetShadowElement()->DistributeSingleNode(aContent);
-    }
-
     // Handle the case where the parent of the insertion point has a ShadowRoot.
     // The node distributed into the insertion point must be reprojected to the
     // insertion points of the parent's ShadowRoot.
     ShadowRoot* parentShadow = insertionPoint->GetParent()->GetShadowRoot();
     if (parentShadow) {
       parentShadow->DistributeSingleNode(aContent);
     }
-
-    // Handle the case where the parent of the insertion point is the <shadow>
-    // element. The node distributed into the insertion point must be reprojected
-    // into the older ShadowRoot's insertion points.
-    if (mShadowElement && mShadowElement == insertionPoint->GetParent()) {
-      ShadowRoot* olderShadow = mShadowElement->GetOlderShadowRoot();
-      if (olderShadow) {
-        olderShadow->DistributeSingleNode(aContent);
-      }
-    }
   }
 }
 
 void
 ShadowRoot::RemoveDistributedNode(nsIContent* aContent)
 {
   // Find insertion point containing the content and remove the node.
   for (uint32_t i = 0; i < mInsertionPoints.Length(); i++) {
@@ -363,63 +325,38 @@ ShadowRoot::RemoveDistributedNode(nsICon
         // Removing the matched node will cause fallback content to be
         // used instead. Give up optimization and distribute all nodes.
         DistributeAllNodes();
         return;
       }
 
       mInsertionPoints[i]->RemoveMatchedNode(aContent);
 
-      // Handle the case where the parent of the insertion point is a ShadowRoot
-      // that is projected into the younger ShadowRoot's shadow insertion point.
-      // The removed node needs to be removed from the shadow insertion point.
-      if (mInsertionPoints[i]->GetParent() == this) {
-        if (mYoungerShadow && mYoungerShadow->GetShadowElement()) {
-          mYoungerShadow->GetShadowElement()->RemoveDistributedNode(aContent);
-        }
-      }
-
       // Handle the case where the parent of the insertion point has a ShadowRoot.
       // The removed node needs to be removed from the insertion points of the
       // parent's ShadowRoot.
       ShadowRoot* parentShadow = mInsertionPoints[i]->GetParent()->GetShadowRoot();
       if (parentShadow) {
         parentShadow->RemoveDistributedNode(aContent);
       }
 
-      // Handle the case where the parent of the insertion point is the <shadow>
-      // element. The removed node must be removed from the older ShadowRoot's
-      // insertion points.
-      if (mShadowElement && mShadowElement == mInsertionPoints[i]->GetParent()) {
-        ShadowRoot* olderShadow = mShadowElement->GetOlderShadowRoot();
-        if (olderShadow) {
-          olderShadow->RemoveDistributedNode(aContent);
-        }
-      }
-
       break;
     }
   }
 }
 
 void
 ShadowRoot::DistributeAllNodes()
 {
   // Create node pool.
   nsTArray<nsIContent*> nodePool;
-
-  // Make sure there is a pool host, an older shadow may not have
-  // one if the younger shadow does not have a <shadow> element.
-  if (mPoolHost) {
-    ExplicitChildIterator childIterator(mPoolHost);
-    for (nsIContent* content = childIterator.GetNextChild();
-         content;
-         content = childIterator.GetNextChild()) {
-      nodePool.AppendElement(content);
-    }
+  ExplicitChildIterator childIterator(GetHost());
+  for (nsIContent* content = childIterator.GetNextChild(); content;
+       content = childIterator.GetNextChild()) {
+    nodePool.AppendElement(content);
   }
 
   nsTArray<ShadowRoot*> shadowsToUpdate;
 
   for (uint32_t i = 0; i < mInsertionPoints.Length(); i++) {
     mInsertionPoints[i]->ClearMatchedNodes();
     // Assign matching nodes from node pool.
     for (uint32_t j = 0; j < nodePool.Length(); j++) {
@@ -440,30 +377,16 @@ ShadowRoot::DistributeAllNodes()
     // to the insertion point must be reprojected to the insertion points of the
     // parent's ShadowRoot.
     ShadowRoot* parentShadow = insertionParent->GetShadowRoot();
     if (parentShadow && !shadowsToUpdate.Contains(parentShadow)) {
       shadowsToUpdate.AppendElement(parentShadow);
     }
   }
 
-  // If there is a shadow insertion point in this ShadowRoot, the children
-  // of the shadow insertion point needs to be distributed into the insertion
-  // points of the older ShadowRoot.
-  if (mShadowElement && mOlderShadow) {
-    mOlderShadow->DistributeAllNodes();
-  }
-
-  // If there is a younger ShadowRoot with a shadow insertion point,
-  // then the children of this ShadowRoot needs to be distributed to
-  // the younger ShadowRoot's shadow insertion point.
-  if (mYoungerShadow && mYoungerShadow->GetShadowElement()) {
-    mYoungerShadow->GetShadowElement()->DistributeAllNodes();
-  }
-
   for (uint32_t i = 0; i < shadowsToUpdate.Length(); i++) {
     shadowsToUpdate[i]->DistributeAllNodes();
   }
 }
 
 void
 ShadowRoot::GetInnerHTML(nsAString& aInnerHTML)
 {
@@ -510,81 +433,27 @@ ShadowRoot::StyleSheets()
 {
   if (!mStyleSheetList) {
     mStyleSheetList = new ShadowRootStyleSheetList(this);
   }
 
   return mStyleSheetList;
 }
 
-void
-ShadowRoot::SetShadowElement(HTMLShadowElement* aShadowElement)
-{
-  // If there is already a shadow element point, remove
-  // the projected shadow because it is no longer an insertion
-  // point.
-  if (mShadowElement) {
-    mShadowElement->SetProjectedShadow(nullptr);
-  }
-
-  if (mOlderShadow) {
-    // Nodes for distribution will come from the new shadow element.
-    mOlderShadow->ChangePoolHost(aShadowElement);
-  }
-
-  // Set the new shadow element to project the older ShadowRoot because
-  // it is the current shadow insertion point.
-  mShadowElement = aShadowElement;
-  if (mShadowElement) {
-    mShadowElement->SetProjectedShadow(mOlderShadow);
-  }
-}
-
-void
-ShadowRoot::ChangePoolHost(nsIContent* aNewHost)
-{
-  if (mPoolHost) {
-    mPoolHost->RemoveMutationObserver(this);
-  }
-
-  // Clear the nodes matched to content insertion points
-  // because it is no longer relevant.
-  for (uint32_t i = 0; i < mInsertionPoints.Length(); i++) {
-    mInsertionPoints[i]->ClearMatchedNodes();
-  }
-
-  mPoolHost = aNewHost;
-  if (mPoolHost) {
-    mPoolHost->AddMutationObserver(this);
-  }
-}
-
-bool
-ShadowRoot::IsShadowInsertionPoint(nsIContent* aContent)
-{
-  if (!aContent) {
-    return false;
-  }
-
-  HTMLShadowElement* shadowElem = HTMLShadowElement::FromContent(aContent);
-  return shadowElem && shadowElem->IsInsertionPoint();
-}
-
 /**
  * Returns whether the web components pool population algorithm
  * on the host would contain |aContent|. This function ignores
  * insertion points in the pool, thus should only be used to
  * test nodes that have not yet been distributed.
  */
 bool
 ShadowRoot::IsPooledNode(nsIContent* aContent, nsIContent* aContainer,
                          nsIContent* aHost)
 {
-  if (nsContentUtils::IsContentInsertionPoint(aContent) ||
-      IsShadowInsertionPoint(aContent)) {
+  if (nsContentUtils::IsContentInsertionPoint(aContent)) {
     // Insertion points never end up in the pool.
     return false;
   }
 
   if (aContainer == aHost &&
       nsContentUtils::IsInSameAnonymousTree(aContainer, aContent)) {
     // Children of the host will end up in the pool. We check to ensure
     // that the content is in the same anonymous tree as the container
@@ -607,17 +476,17 @@ ShadowRoot::IsPooledNode(nsIContent* aCo
 void
 ShadowRoot::AttributeChanged(nsIDocument* aDocument,
                              Element* aElement,
                              int32_t aNameSpaceID,
                              nsIAtom* aAttribute,
                              int32_t aModType,
                              const nsAttrValue* aOldValue)
 {
-  if (!IsPooledNode(aElement, aElement->GetParent(), mPoolHost)) {
+  if (!IsPooledNode(aElement, aElement->GetParent(), GetHost())) {
     return;
   }
 
   // Attributes may change insertion point matching, find its new distribution.
   RemoveDistributedNode(aElement);
   DistributeSingleNode(aElement);
 }
 
@@ -640,17 +509,17 @@ ShadowRoot::ContentAppended(nsIDocument*
     // Add insertion point to destination insertion points of fallback content.
     if (nsContentUtils::IsContentInsertionPoint(aContainer)) {
       HTMLContentElement* content = HTMLContentElement::FromContent(aContainer);
       if (content->MatchedNodes().IsEmpty()) {
         currentChild->DestInsertionPoints().AppendElement(aContainer);
       }
     }
 
-    if (IsPooledNode(currentChild, aContainer, mPoolHost)) {
+    if (IsPooledNode(currentChild, aContainer, GetHost())) {
       DistributeSingleNode(currentChild);
     }
 
     currentChild = currentChild->GetNextSibling();
   }
 }
 
 void
@@ -662,17 +531,17 @@ ShadowRoot::ContentInserted(nsIDocument*
   if (mInsertionPointChanged) {
     DistributeAllNodes();
     mInsertionPointChanged = false;
     return;
   }
 
   // Watch for new nodes added to the pool because the node
   // may need to be added to an insertion point.
-  if (IsPooledNode(aChild, aContainer, mPoolHost)) {
+  if (IsPooledNode(aChild, aContainer, GetHost())) {
     // Add insertion point to destination insertion points of fallback content.
     if (nsContentUtils::IsContentInsertionPoint(aContainer)) {
       HTMLContentElement* content = HTMLContentElement::FromContent(aContainer);
       if (content->MatchedNodes().IsEmpty()) {
         aChild->DestInsertionPoints().AppendElement(aContainer);
       }
     }
 
@@ -699,38 +568,29 @@ ShadowRoot::ContentRemoved(nsIDocument* 
     HTMLContentElement* content = HTMLContentElement::FromContent(aContainer);
     if (content->MatchedNodes().IsEmpty()) {
       aChild->DestInsertionPoints().Clear();
     }
   }
 
   // Watch for node that is removed from the pool because
   // it may need to be removed from an insertion point.
-  if (IsPooledNode(aChild, aContainer, mPoolHost)) {
+  if (IsPooledNode(aChild, aContainer, GetHost())) {
     RemoveDistributedNode(aChild);
   }
 }
 
 nsresult
 ShadowRoot::Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
                   bool aPreallocateChildren) const
 {
   *aResult = nullptr;
   return NS_ERROR_DOM_DATA_CLONE_ERR;
 }
 
-void
-ShadowRoot::DestroyContent()
-{
-  if (mOlderShadow) {
-    mOlderShadow->DestroyContent();
-  }
-  DocumentFragment::DestroyContent();
-}
-
 NS_IMPL_CYCLE_COLLECTION_INHERITED(ShadowRootStyleSheetList, StyleSheetList,
                                    mShadowRoot)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ShadowRootStyleSheetList)
 NS_INTERFACE_MAP_END_INHERITING(StyleSheetList)
 
 NS_IMPL_ADDREF_INHERITED(ShadowRootStyleSheetList, StyleSheetList)
 NS_IMPL_RELEASE_INHERITED(ShadowRootStyleSheetList, StyleSheetList)

--- a/dom/base/ShadowRoot.h
+++ b/dom/base/ShadowRoot.h
@@ -20,61 +20,43 @@ class nsIAtom;
 class nsIContent;
 class nsXBLPrototypeBinding;
 
 namespace mozilla {
 namespace dom {
 
 class Element;
 class HTMLContentElement;
-class HTMLShadowElement;
 class ShadowRootStyleSheetList;
 
 class ShadowRoot final : public DocumentFragment,
                          public nsStubMutationObserver
 {
   friend class ShadowRootStyleSheetList;
 public:
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ShadowRoot,
                                            DocumentFragment)
   NS_DECL_ISUPPORTS_INHERITED
 
   NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
 
-  ShadowRoot(Element* aElement, already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
+  ShadowRoot(Element* aElement,
+             already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
              nsXBLPrototypeBinding* aProtoBinding);
 
   void AddToIdTable(Element* aElement, nsIAtom* aId);
   void RemoveFromIdTable(Element* aElement, nsIAtom* aId);
   void InsertSheet(StyleSheet* aSheet, nsIContent* aLinkingContent);
   void RemoveSheet(StyleSheet* aSheet);
   bool ApplyAuthorStyles();
   void SetApplyAuthorStyles(bool aApplyAuthorStyles);
   StyleSheetList* StyleSheets();
-  HTMLShadowElement* GetShadowElement() { return mShadowElement; }
-
-  /**
-   * Sets the current shadow insertion point where the older
-   * ShadowRoot will be projected.
-   */
-  void SetShadowElement(HTMLShadowElement* aShadowElement);
-
-  /**
-   * Change the node that populates the distribution pool with
-   * its children. This is distinct from the ShadowRoot host described
-   * in the specifications. The ShadowRoot host is the element
-   * which created this ShadowRoot and does not change. The pool host
-   * is the same as the ShadowRoot host if this is the youngest
-   * ShadowRoot. If this is an older ShadowRoot, the pool host is
-   * the <shadow> element in the younger ShadowRoot (if it exists).
-   */
-  void ChangePoolHost(nsIContent* aNewHost);
 
   /**
    * Distributes a single explicit child of the pool host to the content
    * insertion points in this ShadowRoot.
    */
   void DistributeSingleNode(nsIContent* aContent);
 
   /**
@@ -87,98 +69,69 @@ public:
    * Distributes all the explicit children of the pool host to the content
    * insertion points in this ShadowRoot.
    */
   void DistributeAllNodes();
 
   void AddInsertionPoint(HTMLContentElement* aInsertionPoint);
   void RemoveInsertionPoint(HTMLContentElement* aInsertionPoint);
 
-  void SetYoungerShadow(ShadowRoot* aYoungerShadow);
-  ShadowRoot* GetYoungerShadowRoot() { return mYoungerShadow; }
   void SetInsertionPointChanged() { mInsertionPointChanged = true; }
 
   void SetAssociatedBinding(nsXBLBinding* aBinding) { mAssociatedBinding = aBinding; }
 
-  nsISupports* GetParentObject() const { return mPoolHost; }
-
-  nsIContent* GetPoolHost() { return mPoolHost; }
-  nsTArray<HTMLShadowElement*>& ShadowDescendants() { return mShadowDescendants; }
-
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   static bool IsPooledNode(nsIContent* aChild, nsIContent* aContainer,
                            nsIContent* aHost);
   static ShadowRoot* FromNode(nsINode* aNode);
-  static bool IsShadowInsertionPoint(nsIContent* aContent);
 
   static void RemoveDestInsertionPoint(nsIContent* aInsertionPoint,
                                        nsTArray<nsIContent*>& aDestInsertionPoints);
 
   // WebIDL methods.
   Element* GetElementById(const nsAString& aElementId);
   already_AddRefed<nsContentList>
     GetElementsByTagName(const nsAString& aNamespaceURI);
   already_AddRefed<nsContentList>
     GetElementsByTagNameNS(const nsAString& aNamespaceURI,
                            const nsAString& aLocalName);
   already_AddRefed<nsContentList>
     GetElementsByClassName(const nsAString& aClasses);
   void GetInnerHTML(nsAString& aInnerHTML);
   void SetInnerHTML(const nsAString& aInnerHTML, ErrorResult& aError);
   Element* Host();
-  ShadowRoot* GetOlderShadowRoot() { return mOlderShadow; }
   void StyleSheetChanged();
 
   bool IsComposedDocParticipant() { return mIsComposedDocParticipant; }
   void SetIsComposedDocParticipant(bool aIsComposedDocParticipant)
   {
     mIsComposedDocParticipant = aIsComposedDocParticipant;
   }
 
-  virtual void DestroyContent() override;
 protected:
   virtual ~ShadowRoot();
 
-  // The pool host is the parent of the nodes that will be distributed
-  // into the insertion points in this ShadowRoot. See |ChangeShadowRoot|.
-  nsCOMPtr<nsIContent> mPoolHost;
-
   // An array of content insertion points that are a descendant of the ShadowRoot
   // sorted in tree order. Insertion points are responsible for notifying
   // the ShadowRoot when they are removed or added as a descendant. The insertion
   // points are kept alive by the parent node, thus weak references are held
   // by the array.
   nsTArray<HTMLContentElement*> mInsertionPoints;
 
-  // An array of the <shadow> elements that are descendant of the ShadowRoot
-  // sorted in tree order. Only the first may be a shadow insertion point.
-  nsTArray<HTMLShadowElement*> mShadowDescendants;
-
   nsTHashtable<nsIdentifierMapEntry> mIdentifierMap;
   nsXBLPrototypeBinding* mProtoBinding;
 
   // It is necessary to hold a reference to the associated nsXBLBinding
   // because the binding holds a reference on the nsXBLDocumentInfo that
   // owns |mProtoBinding|.
   RefPtr<nsXBLBinding> mAssociatedBinding;
 
   RefPtr<ShadowRootStyleSheetList> mStyleSheetList;
 
-  // The current shadow insertion point of this ShadowRoot.
-  HTMLShadowElement* mShadowElement;
-
-  // The ShadowRoot that was created by the host element before
-  // this ShadowRoot was created.
-  RefPtr<ShadowRoot> mOlderShadow;
-
-  // The ShadowRoot that was created by the host element after
-  // this ShadowRoot was created.
-  RefPtr<ShadowRoot> mYoungerShadow;
-
   // A boolean that indicates that an insertion point was added or removed
   // from this ShadowRoot and that the nodes need to be redistributed into
   // the insertion points. After this flag is set, nodes will be distributed
   // on the next mutation event.
   bool mInsertionPointChanged;
 
   // Flag to indicate whether the descendants of this shadow root are part of the
   // composed document. Ideally, we would use a node flag on nodes to

--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -180,16 +180,17 @@ EXPORTS.mozilla.dom += [
     'FormData.h',
     'FragmentOrElement.h',
     'FromParser.h',
     'GroupedSHistory.h',
     'IdleDeadline.h',
     'IdleRequest.h',
     'ImageEncoder.h',
     'ImageTracker.h',
+    'IntlUtils.h',
     'Link.h',
     'Location.h',
     'NameSpaceConstants.h',
     'Navigator.h',
     'NodeInfo.h',
     'NodeInfoInlines.h',
     'NodeIterator.h',
     'PartialSHistory.h',
@@ -253,16 +254,17 @@ UNIFIED_SOURCES += [
     'EventSource.cpp',
     'FormData.cpp',
     'FragmentOrElement.cpp',
     'GroupedSHistory.cpp',
     'IdleDeadline.cpp',
     'IdleRequest.cpp',
     'ImageEncoder.cpp',
     'ImageTracker.cpp',
+    'IntlUtils.cpp',
     'Link.cpp',
     'Location.cpp',
     'Navigator.cpp',
     'NodeInfo.cpp',
     'NodeIterator.cpp',
     'nsAtomListUtils.cpp',
     'nsAttrAndChildArray.cpp',
     'nsAttrValue.cpp',
@@ -370,24 +372,16 @@ if CONFIG['MOZ_WEBRTC']:
         'nsDOMDataChannel.cpp',
     ]
 
 if CONFIG['FUZZING']:
     UNIFIED_SOURCES += [
         'FuzzingFunctions.cpp',
     ]
 
-if CONFIG['ENABLE_INTL_API']:
-    UNIFIED_SOURCES += [
-        'IntlUtils.cpp',
-    ]
-    EXPORTS.mozilla.dom += [
-        'IntlUtils.h',
-    ]
-
 # these files couldn't be in UNIFIED_SOURCES for now for reasons given below:
 SOURCES += [
     # Several conflicts with other bindings.
     'DOMIntersectionObserver.cpp',
     # Because of OS X headers.
     'nsContentUtils.cpp',
     # this file doesn't like windows.h
     'nsDOMWindowUtils.cpp',

--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -45,17 +45,16 @@
 #include "mozilla/dom/DOMTypes.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ElementInlines.h"
 #include "mozilla/dom/FileSystemSecurity.h"
 #include "mozilla/dom/FileBlobImpl.h"
 #include "mozilla/dom/HTMLInputElement.h"
 #include "mozilla/dom/HTMLTemplateElement.h"
 #include "mozilla/dom/HTMLContentElement.h"
-#include "mozilla/dom/HTMLShadowElement.h"
 #include "mozilla/dom/IPCBlobUtils.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/TabParent.h"
 #include "mozilla/dom/TouchEvent.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "mozilla/dom/XULCommandEvent.h"
 #include "mozilla/dom/WorkerPrivate.h"
@@ -7562,30 +7561,16 @@ nsContentUtils::HasDistributedChildren(n
   }
 
   if (aContent->GetShadowRoot()) {
     // Children of a shadow root host are distributed
     // to content insertion points in the shadow root.
     return true;
   }
 
-  ShadowRoot* shadow = ShadowRoot::FromNode(aContent);
-  if (shadow) {
-    // Children of a shadow root are distributed to
-    // the shadow insertion point of the younger shadow root.
-    return shadow->GetYoungerShadowRoot();
-  }
-
-  HTMLShadowElement* shadowEl = HTMLShadowElement::FromContent(aContent);
-  if (shadowEl && shadowEl->IsInsertionPoint()) {
-    // Children of a shadow insertion points are distributed
-    // to the insertion points in the older shadow root.
-    return shadowEl->GetOlderShadowRoot();
-  }
-
   HTMLContentElement* contentEl = HTMLContentElement::FromContent(aContent);
   if (contentEl && contentEl->IsInsertionPoint()) {
     // Children of a content insertion point are distributed to the
     // content insertion point if the content insertion point does
     // not match any nodes (fallback content).
     return contentEl->MatchedNodes().IsEmpty();
   }
 
@@ -10150,16 +10135,59 @@ nsContentUtils::GetElementDefinitionIfOb
   if (!definition || !definition->IsInObservedAttributeList(aAttrName)) {
     return nullptr;
   }
 
   return definition;
 }
 
 /* static */ void
+nsContentUtils::SyncInvokeReactions(nsIDocument::ElementCallbackType aType,
+                                    Element* aElement,
+                                    CustomElementDefinition* aDefinition)
+{
+  MOZ_ASSERT(aElement);
+
+  nsIDocument* doc = aElement->OwnerDoc();
+  nsPIDOMWindowInner* window(doc->GetInnerWindow());
+  if (!window) {
+    return;
+  }
+
+  RefPtr<CustomElementRegistry> registry(window->CustomElements());
+  if (!registry) {
+    return;
+  }
+
+  registry->SyncInvokeReactions(aType, aElement, aDefinition);
+}
+
+/* static */ void
+nsContentUtils::EnqueueUpgradeReaction(Element* aElement,
+                                       CustomElementDefinition* aDefinition)
+{
+  MOZ_ASSERT(aElement);
+
+  nsIDocument* doc = aElement->OwnerDoc();
+  nsPIDOMWindowInner* window(doc->GetInnerWindow());
+  if (!window) {
+    return;
+  }
+
+  RefPtr<CustomElementRegistry> registry(window->CustomElements());
+  if (!registry) {
+    return;
+  }
+
+  CustomElementReactionsStack* stack =
+    doc->GetDocGroup()->CustomElementReactionsStack();
+  stack->EnqueueUpgradeReaction(registry, aElement, aDefinition);
+}
+
+/* static */ void
 nsContentUtils::EnqueueLifecycleCallback(nsIDocument* aDoc,
                                          nsIDocument::ElementCallbackType aType,
                                          Element* aCustomElement,
                                          LifecycleCallbackArgs* aArgs,
                                          CustomElementDefinition* aDefinition)
 {
   MOZ_ASSERT(aDoc);
 

--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -2993,16 +2993,23 @@ public:
   static void SetupCustomElement(Element* aElement,
                                  const nsAString* aTypeExtension = nullptr);
 
   static mozilla::dom::CustomElementDefinition*
   GetElementDefinitionIfObservingAttr(Element* aCustomElement,
                                       nsIAtom* aExtensionType,
                                       nsIAtom* aAttrName);
 
+  static void SyncInvokeReactions(nsIDocument::ElementCallbackType aType,
+                                  Element* aCustomElement,
+                                  mozilla::dom::CustomElementDefinition* aDefinition);
+
+  static void EnqueueUpgradeReaction(Element* aElement,
+                                     mozilla::dom::CustomElementDefinition* aDefinition);
+
   static void EnqueueLifecycleCallback(nsIDocument* aDoc,
                                        nsIDocument::ElementCallbackType aType,
                                        Element* aCustomElement,
                                        mozilla::dom::LifecycleCallbackArgs* aArgs = nullptr,
                                        mozilla::dom::CustomElementDefinition* aDefinition = nullptr);
 
   static void GetCustomPrototype(nsIDocument* aDoc,
                                  int32_t aNamespaceID,

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -274,16 +274,17 @@
 #include "nsISpeculativeConnect.h"
 
 #include "mozilla/MediaManager.h"
 
 #include "nsIURIClassifier.h"
 #include "mozilla/DocumentStyleRootIterator.h"
 #include "mozilla/ServoRestyleManager.h"
 #include "mozilla/ClearOnShutdown.h"
+#include "nsHTMLTags.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
 
 typedef nsTArray<Link*> LinkArray;
 
 static LazyLogModule gDocumentLeakPRLog("DocumentLeak");
 static LazyLogModule gCspPRLog("CSP");
@@ -6019,16 +6020,20 @@ nsDocument::CreateElement(const nsAStrin
 
   RefPtr<Element> elem = CreateElem(
     needsLowercase ? lcTagName : aTagName, nullptr, mDefaultElementType, is);
 
   if (pseudoType != CSSPseudoElementType::NotPseudo) {
     elem->SetPseudoElementType(pseudoType);
   }
 
+  if (is) {
+    elem->SetAttr(kNameSpaceID_None, nsGkAtoms::is, *is, true);
+  }
+
   return elem.forget();
 }
 
 NS_IMETHODIMP
 nsDocument::CreateElementNS(const nsAString& aNamespaceURI,
                             const nsAString& aQualifiedName,
                             nsIDOMElement** aReturn)
 {
@@ -6070,16 +6075,20 @@ nsDocument::CreateElementNS(const nsAStr
 
   nsCOMPtr<Element> element;
   rv = NS_NewElement(getter_AddRefs(element), nodeInfo.forget(),
                      NOT_FROM_PARSER, is);
   if (rv.Failed()) {
     return nullptr;
   }
 
+  if (is) {
+    element->SetAttr(kNameSpaceID_None, nsGkAtoms::is, *is, true);
+  }
+
   return element.forget();
 }
 
 NS_IMETHODIMP
 nsDocument::CreateTextNode(const nsAString& aData, nsIDOMText** aReturn)
 {
   *aReturn = nsIDocument::CreateTextNode(aData).take();
   return NS_OK;
@@ -6352,21 +6361,36 @@ nsDocument::CustomElementConstructor(JSC
       if (!JS_WrapObject(aCx, &reflector)) {
         return false;
       }
 
       args.rval().setObject(*reflector);
       return true;
     }
   } else {
-    nsDependentAtomString localName(definition->mLocalName);
-    element =
-      document->CreateElem(localName, nullptr, kNameSpaceID_XHTML,
-                           (definition->mLocalName != typeAtom) ? &elemName
-                                                                : nullptr);
+    RefPtr<mozilla::dom::NodeInfo> nodeInfo =
+      document->NodeInfoManager()->GetNodeInfo(definition->mLocalName, nullptr,
+                                               kNameSpaceID_XHTML,
+                                               nsIDOMNode::ELEMENT_NODE);
+
+    int32_t tag = nsHTMLTags::CaseSensitiveAtomTagToId(definition->mLocalName);
+    if (tag == eHTMLTag_userdefined &&
+        nsContentUtils::IsCustomElementName(definition->mType)) {
+      element = NS_NewHTMLElement(nodeInfo.forget(), NOT_FROM_PARSER);
+    } else {
+      element = ::CreateHTMLElement(tag, nodeInfo.forget(), NOT_FROM_PARSER);
+    }
+
+    element->SetCustomElementData(
+      new CustomElementData(definition->mType,
+                            CustomElementData::State::eCustom));
+
+    // It'll be removed when we deprecate custom elements v0.
+    nsContentUtils::SyncInvokeReactions(nsIDocument::eCreated, element,
+                                        definition);
     NS_ENSURE_TRUE(element, false);
   }
 
   // The prototype setup happens in Element::WrapObject().
   nsresult rv = nsContentUtils::WrapNative(aCx, element, element, args.rval());
   NS_ENSURE_SUCCESS(rv, true);
 
   return true;