--- a/browser/components/preferences/in-content/privacy.js
+++ b/browser/components/preferences/in-content/privacy.js
@@ -646,32 +646,32 @@ var gPrivacyPane = {
     gSubDialog.open("chrome://browser/content/preferences/sanitize.xul", "resizable=no");
   },
 
 
   /**
    * Displays a dialog from which individual parts of private data may be
    * cleared.
    */
-  clearPrivateDataNow: function (aClearEverything)
-  {
+  clearPrivateDataNow: function (aClearEverything) {
     var ts = document.getElementById("privacy.sanitize.timeSpan");
     var timeSpanOrig = ts.value;
-    if (aClearEverything)
+
+    if (aClearEverything) {
       ts.value = 0;
+    }
 
-    const Cc = Components.classes, Ci = Components.interfaces;
-    var glue = Cc["@mozilla.org/browser/browserglue;1"]
-                 .getService(Ci.nsIBrowserGlue);
-    glue.sanitize(window);
+    gSubDialog.open("chrome://browser/content/sanitize.xul", "resizable=no", null, () => {
+      // reset the timeSpan pref
+      if (aClearEverything) {
+        ts.value = timeSpanOrig;
+      }
 
-    // reset the timeSpan pref
-    if (aClearEverything)
-      ts.value = timeSpanOrig;
-    Services.obs.notifyObservers(null, "clear-private-data", null);
+      Services.obs.notifyObservers(null, "clear-private-data", null);
+    });
   },
 
   /**
    * Enables or disables the "Settings..." button depending
    * on the privacy.sanitize.sanitizeOnShutdown preference value
    */
   _updateSanitizeSettingsButton: function () {
     var settingsButton = document.getElementById("clearDataSettings");

--- a/browser/components/preferences/in-content/subdialogs.js
+++ b/browser/components/preferences/in-content/subdialogs.js
@@ -168,16 +168,28 @@ var gSubDialog = {
       this.injectXMLStylesheet(styleSheetURL);
     }
 
     // Provide the ability for the dialog to know that it is being loaded "in-content".
     this._frame.contentDocument.documentElement.setAttribute("subdialog", "true");
 
     this._frame.contentWindow.addEventListener("dialogclosing", this);
 
+    let oldResizeBy = this._frame.contentWindow.resizeBy;
+    this._frame.contentWindow.resizeBy = function(resizeByWidth, resizeByHeight) {
+      // Only handle resizeByHeight currently.
+      let frameHeight = gSubDialog._frame.clientHeight;
+      let boxMinHeight = parseFloat(getComputedStyle(gSubDialog._box).minHeight, 10);
+
+      gSubDialog._frame.style.height = (frameHeight + resizeByHeight) + "px";
+      gSubDialog._box.style.minHeight = (boxMinHeight + resizeByHeight) + "px";
+
+      oldResizeBy.call(gSubDialog._frame.contentWindow, resizeByWidth, resizeByHeight);
+    };
+
     // Make window.close calls work like dialog closing.
     let oldClose = this._frame.contentWindow.close;
     this._frame.contentWindow.close = function() {
       var closingEvent = gSubDialog._closingEvent;
       if (!closingEvent) {
         closingEvent = new CustomEvent("dialogclosing", {
           bubbles: true,
           detail: { button: null },
@@ -268,18 +280,20 @@ var gSubDialog = {
     this._frame.style.height = frameHeight;
     this._box.style.minHeight = "calc(" +
                                 (boxVerticalBorder + groupBoxTitleHeight + boxVerticalPadding) +
                                 "px + " + frameMinHeight + ")";
 
     this._overlay.style.visibility = "visible";
     this._overlay.style.opacity = ""; // XXX: focus hack continued from _onContentLoaded
 
-    this._resizeObserver = new MutationObserver(this._onResize);
-    this._resizeObserver.observe(this._box, {attributes: true});
+    if (this._box.getAttribute("resizable") == "true") {
+      this._resizeObserver = new MutationObserver(this._onResize);
+      this._resizeObserver.observe(this._box, {attributes: true});
+    }
 
     this._trapFocus();
   },
 
   _onResize: function(mutations) {
     let frame = gSubDialog._frame;
     // The width and height styles are needed for the initial
     // layout of the frame, but afterward they need to be removed

--- a/browser/themes/linux/sanitizeDialog.css
+++ b/browser/themes/linux/sanitizeDialog.css
@@ -51,17 +51,17 @@
 }
 
 
 /* Progressive disclosure button */
 #detailsExpanderWrapper {
   padding: 0;
   margin-top: 6px;
   margin-bottom: 6px;
-  margin-inline-start: -6px;
+  margin-inline-start: -4px;
   margin-inline-end: 0;
 }
 
 .expander-up,
 .expander-down {
   min-width: 0;
   padding: 2px 0;
   padding-inline-start: 2px;

--- a/browser/themes/shared/incontentprefs/preferences.inc.css
+++ b/browser/themes/shared/incontentprefs/preferences.inc.css
@@ -364,17 +364,16 @@ description > html|a {
 #dialogBox > .groupbox-body {
   -moz-appearance: none;
   padding: 20px;
 }
 
 #dialogFrame {
   -moz-box-flex: 1;
   /* Default dialog dimensions */
-  height: 20em;
   width: 66ch;
 }
 
 .largeDialogContainer.doScroll {
   overflow-y: auto;
   -moz-box-flex: 1;
 }
 

--- a/browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Preferences.jsm
+++ b/browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Preferences.jsm
@@ -18,16 +18,17 @@ this.Preferences = {
   init(libDir) {
     let panes = [
       ["paneGeneral", null],
       ["paneSearch", null],
       ["paneContent", null],
       ["paneApplications", null],
       ["panePrivacy", null],
       ["panePrivacy", null, DNTDialog],
+      ["panePrivacy", null, clearRecentHistoryDialog],
       ["paneSecurity", null],
       ["paneSync", null],
       ["paneAdvanced", "generalTab"],
       ["paneAdvanced", "dataChoicesTab"],
       ["paneAdvanced", "networkTab"],
       ["paneAdvanced", "networkTab", connectionDialog],
       ["paneAdvanced", "updateTab"],
       ["paneAdvanced", "encryptionTab"],
@@ -102,16 +103,22 @@ function* DNTDialog(aBrowser) {
 }
 
 function* connectionDialog(aBrowser) {
   yield ContentTask.spawn(aBrowser, null, function* () {
     content.document.getElementById("connectionSettings").click();
   });
 }
 
+function* clearRecentHistoryDialog(aBrowser) {
+  yield ContentTask.spawn(aBrowser, null, function* () {
+    content.document.getElementById("historyRememberClear").click();
+  });
+}
+
 function* certManager(aBrowser) {
   yield ContentTask.spawn(aBrowser, null, function* () {
     content.document.getElementById("viewCertificatesButton").click();
   });
 }
 
 function* deviceManager(aBrowser) {
   yield ContentTask.spawn(aBrowser, null, function* () {