--- a/browser/base/content/test/general/browser_bug553455.js
+++ b/browser/base/content/test/general/browser_bug553455.js
@@ -874,20 +874,23 @@ function test() {
   Services.prefs.setBoolPref("extensions.logging.enabled", true);
   Services.prefs.setBoolPref("extensions.strictCompatibility", true);
 
   Services.obs.addObserver(XPInstallObserver, "addon-install-started", false);
   Services.obs.addObserver(XPInstallObserver, "addon-install-blocked", false);
   Services.obs.addObserver(XPInstallObserver, "addon-install-failed", false);
   Services.obs.addObserver(XPInstallObserver, "addon-install-complete", false);
 
+  PopupNotifications.transitionsEnabled = false;
+
   registerCleanupFunction(function() {
     // Make sure no more test parts run in case we were timed out
     TESTS = [];
     PopupNotifications.panel.removeEventListener("popupshown", check_notification, false);
+    PopupNotifications.transitionsEnabled = true;
 
     AddonManager.getAllInstalls(function(aInstalls) {
       aInstalls.forEach(function(aInstall) {
         aInstall.cancel();
       });
     });
 
     Services.prefs.clearUserPref("extensions.logging.enabled");

--- a/browser/base/content/test/general/browser_customize_popupNotification.js
+++ b/browser/base/content/test/general/browser_customize_popupNotification.js
@@ -7,21 +7,24 @@ function test() {
   waitForExplicitFinish();
   let newWin = OpenBrowserWindow();
   whenDelayedStartupFinished(newWin, function () {
     // Remove the URL bar
     newWin.gURLBar.parentNode.removeChild(newWin.gURLBar);
 
     waitForFocus(function () {
       let PN = newWin.PopupNotifications;
+      PN.transitionsEnabled = false;
       try {
         let notification = PN.show(newWin.gBrowser.selectedBrowser, "some-notification", "Some message");
         ok(notification, "showed the notification");
         ok(PN.isPanelOpen, "panel is open");
         is(PN.panel.anchorNode, newWin.gBrowser.selectedTab, "notification is correctly anchored to the tab");
+        PN.panel.hidePopup();
       } catch (ex) {
         ok(false, "threw exception: " + ex);
       }
+      PN.transitionsEnabled = true;
       newWin.close();
       finish();
     }, newWin);
   });
 }

--- a/browser/base/content/test/general/browser_popupNotification.js
+++ b/browser/base/content/test/general/browser_popupNotification.js
@@ -3,27 +3,32 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 function test() {
   waitForExplicitFinish();
 
   ok(PopupNotifications, "PopupNotifications object exists");
   ok(PopupNotifications.panel, "PopupNotifications panel exists");
 
+  // Disable transitions as they slow the test down and we want to click the
+  // mouse buttons in a predictable location.
+  PopupNotifications.transitionsEnabled = false;
+
   registerCleanupFunction(cleanUp);
 
   runNextTest();
 }
 
 function cleanUp() {
   for (var topic in gActiveObservers)
     Services.obs.removeObserver(gActiveObservers[topic], topic);
   for (var eventName in gActiveListeners)
     PopupNotifications.panel.removeEventListener(eventName, gActiveListeners[eventName], false);
   PopupNotifications.buttonDelay = PREF_SECURITY_DELAY_INITIAL;
+  PopupNotifications.transitionsEnabled = true;
 }
 
 const PREF_SECURITY_DELAY_INITIAL = Services.prefs.getIntPref("security.notification_enable_delay");
 
 var gActiveListeners = {};
 var gActiveObservers = {};
 var gShownState = {};
 

--- a/browser/components/customizableui/test/browser_884402_customize_from_overflow.js
+++ b/browser/components/customizableui/test/browser_884402_customize_from_overflow.js
@@ -1,22 +1,26 @@
 "use strict";
 
 let overflowPanel = document.getElementById("widget-overflow");
 
 const isOSX = (Services.appinfo.OS === "Darwin");
 
 let originalWindowWidth;
 registerCleanupFunction(function() {
+  overflowPanel.removeAttribute("animate");
   window.resizeTo(originalWindowWidth, window.outerHeight);
 });
 
 // Right-click on an item within the overflow panel should
 // show a context menu with options to move it.
 add_task(function() {
+
+  overflowPanel.setAttribute("animate", "false");
+
   originalWindowWidth = window.outerWidth;
   let navbar = document.getElementById(CustomizableUI.AREA_NAVBAR);
   ok(!navbar.hasAttribute("overflowing"), "Should start with a non-overflowing toolbar.");
   let oldChildCount = navbar.customizationTarget.childElementCount;
   window.resizeTo(400, window.outerHeight);
 
   yield waitForCondition(() => navbar.hasAttribute("overflowing"));
   ok(navbar.hasAttribute("overflowing"), "Should have an overflowing toolbar.");

--- a/browser/components/places/tests/browser/browser_toolbarbutton_menu_context.js
+++ b/browser/components/places/tests/browser/browser_toolbarbutton_menu_context.js
@@ -12,27 +12,29 @@ add_task(function testPopup() {
   CustomizableUI.addWidgetToArea("bookmarks-menu-button", CustomizableUI.AREA_PANEL);
   CustomizableUI.addWidgetToArea("bookmarks-menu-button", CustomizableUI.AREA_NAVBAR, pos);
   info("Checking popup context menu after moving the bookmarks button");
   yield checkPopupContextMenu();
 });
 
 function* checkPopupContextMenu() {
   let dropmarker = document.getAnonymousElementByAttribute(bookmarksMenuButton, "anonid", "dropmarker");
+  BMB_menuPopup.setAttribute("style", "transition: none;");
   let popupShownPromise = onPopupEvent(BMB_menuPopup, "shown");
   EventUtils.synthesizeMouseAtCenter(dropmarker, {});
   info("Waiting for bookmarks menu to be shown.");
   yield popupShownPromise;
   let contextMenuShownPromise = onPopupEvent(contextMenu, "shown");
   EventUtils.synthesizeMouseAtCenter(BMB_showAllBookmarks, {type: "contextmenu", button: 2 });
   info("Waiting for context menu on bookmarks menu to be shown.");
   yield contextMenuShownPromise;
   ok(!newBookmarkItem.hasAttribute("disabled"), "New bookmark item shouldn't be disabled");
   let contextMenuHiddenPromise = onPopupEvent(contextMenu, "hidden");
   contextMenu.hidePopup();
+  BMB_menuPopup.removeAttribute("style");
   info("Waiting for context menu on bookmarks menu to be hidden.");
   yield contextMenuHiddenPromise;
   let popupHiddenPromise = onPopupEvent(BMB_menuPopup, "hidden");
   // Can't use synthesizeMouseAtCenter because the dropdown panel is in the way
   EventUtils.synthesizeKey("VK_ESCAPE", {});
   info("Waiting for bookmarks menu to be hidden.");
   yield popupHiddenPromise;
 }

--- a/browser/devtools/shared/widgets/Tooltip.js
+++ b/browser/devtools/shared/widgets/Tooltip.js
@@ -98,16 +98,17 @@ let PanelFactory = {
    * @param {OptionsStore} options
    *        An options store to get some configuration from
    */
   get: function(doc, options) {
     // Create the tooltip
     let panel = doc.createElement("panel");
     panel.setAttribute("hidden", true);
     panel.setAttribute("ignorekeys", true);
+    panel.setAttribute("animate", false);
 
     panel.setAttribute("consumeoutsideclicks", options.get("consumeOutsideClick"));
     panel.setAttribute("noautofocus", options.get("noAutoFocus"));
     panel.setAttribute("type", "arrow");
     panel.setAttribute("level", "top");
 
     panel.setAttribute("class", "devtools-tooltip theme-tooltip-panel");
     doc.querySelector("window").appendChild(panel);

--- a/browser/modules/test/browser_SignInToWebsite.js
+++ b/browser/modules/test/browser_SignInToWebsite.js
@@ -271,16 +271,18 @@ function test() {
   try {
     Components.utils.import("resource:///modules/SignInToWebsite.jsm", sitw);
   } catch (ex) {
     ok(true, "Skip the test since SignInToWebsite.jsm isn't packaged outside outside mozilla-central");
     finish();
     return;
   }
 
+  PopupNotifications.transitionsEnabled = false;
+
   registerCleanupFunction(cleanUp);
 
   ok(sitw.SignInToWebsiteUX, "SignInToWebsiteUX object exists");
   if (!Services.prefs.getBoolPref("dom.identity.enabled")) {
     // If the pref isn't enabled then init wasn't called so do that for the test.
     sitw.SignInToWebsiteUX.init();
   }
 
@@ -308,16 +310,18 @@ function resetState() {
   IdentityService.reset();
 }
 
 // Cleanup after all tests
 function cleanUp() {
   info("cleanup");
   resetState();
 
+  PopupNotifications.transitionsEnabled = true;
+
   for (let topic in gActiveObservers)
     Services.obs.removeObserver(gActiveObservers[topic], topic);
   for (let eventName in gActiveListeners)
     PopupNotifications.panel.removeEventListener(eventName, gActiveListeners[eventName], false);
   delete IdentityService.RP._rpFlows[outerWinId];
 
   // Put the JSM functions back to how they were
   IdentityService.IDP.setAuthenticationFlow = window.setAuthenticationFlow;

--- a/browser/modules/test/browser_UITour3.js
+++ b/browser/modules/test/browser_UITour3.js
@@ -18,16 +18,20 @@ function test() {
 let tests = [
   function test_info_icon(done) {
     let popup = document.getElementById("UITourTooltip");
     let title = document.getElementById("UITourTooltipTitle");
     let desc = document.getElementById("UITourTooltipDescription");
     let icon = document.getElementById("UITourTooltipIcon");
     let buttons = document.getElementById("UITourTooltipButtons");
 
+    // Disable the animation to prevent the mouse clicks from hitting the main
+    // window during the transition instead of the buttons in the popup.
+    popup.setAttribute("animate", "false");
+
     popup.addEventListener("popupshown", function onPopupShown() {
       popup.removeEventListener("popupshown", onPopupShown);
 
       is(title.textContent, "a title", "Popup should have correct title");
       is(desc.textContent, "some text", "Popup should have correct description text");
 
       let imageURL = getRootDirectory(gTestPath) + "image.png";
       imageURL = imageURL.replace("chrome://mochitests/content/", "https://example.com/");
@@ -145,16 +149,17 @@ let tests = [
   function test_info_target_callback(done) {
     let popup = document.getElementById("UITourTooltip");
     popup.addEventListener("popupshown", function onPopupShown() {
       popup.removeEventListener("popupshown", onPopupShown);
       PanelUI.show().then(() => {
         is(gContentWindow.callbackResult, "target", "target callback called");
         is(gContentWindow.callbackData.target, "appMenu", "target callback was from the appMenu");
         is(gContentWindow.callbackData.type, "popupshown", "target callback was from the mousedown");
+        popup.removeAttribute("animate");
         done();
       });
     });
 
     let infoOptions = gContentWindow.makeInfoOptions();
     gContentAPI.showInfo("appMenu", "I want to know when the target is clicked", "*click*", null, null, infoOptions);
   },
 ];

--- a/dom/indexedDB/test/browser_permissionsPromptAllow.js
+++ b/dom/indexedDB/test/browser_permissionsPromptAllow.js
@@ -5,16 +5,19 @@
 
 const testPageURL = "http://mochi.test:8888/browser/" +
   "dom/indexedDB/test/browser_permissionsPrompt.html";
 const notificationID = "indexedDB-permissions-prompt";
 
 function test()
 {
   waitForExplicitFinish();
+
+  PopupNotifications.transitionsEnabled = false;
+
   // We want a prompt.
   setPermission(testPageURL, "indexedDB", "allow");
   executeSoon(test1);
 }
 
 function test1()
 {
   info("creating tab");
@@ -64,16 +67,17 @@ function test2()
          "First database creation was successful");
       ok(!exception, "No exception");
       is(getPermission(testPageURL, "indexedDB"),
          Components.interfaces.nsIPermissionManager.UNKNOWN_ACTION,
          "Correct permission set");
       gBrowser.removeCurrentTab();
       unregisterAllPopupEventHandlers();
       removePermission(testPageURL, "indexedDB");
+      PopupNotifications.transitionsEnabled = true;
       executeSoon(finish);
     });
 
     registerPopupEventHandler("popupshowing", function () {
       ok(false, "Shouldn't show a popup this time");
     });
     registerPopupEventHandler("popupshown", function () {
       ok(false, "Shouldn't show a popup this time");

--- a/dom/indexedDB/test/browser_permissionsPromptDeny.js
+++ b/dom/indexedDB/test/browser_permissionsPromptDeny.js
@@ -6,16 +6,17 @@
 const testPageURL = "http://mochi.test:8888/browser/" +
   "dom/indexedDB/test/browser_permissionsPrompt.html";
 const notificationID = "indexedDB-permissions-prompt";
 
 function test()
 {
   waitForExplicitFinish();
   // We want the prompt.
+  PopupNotifications.transitionsEnabled = false;
   setPermission(testPageURL, "indexedDB", "allow");
   executeSoon(test1);
 }
 
 function test1()
 {
   info("creating tab");
   gBrowser.selectedTab = gBrowser.addTab();
@@ -63,16 +64,17 @@ function test2()
       ok(!result, "No database created");
       is(exception, "InvalidStateError", "Correct exception");
       is(getPermission(testPageURL, "indexedDB"),
          Components.interfaces.nsIPermissionManager.DENY_ACTION,
          "Correct permission set");
       gBrowser.selectedBrowser.docShell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing = false;
       unregisterAllPopupEventHandlers();
       gBrowser.removeCurrentTab();
+      PopupNotifications.transitionsEnabled = true;
       executeSoon(test3);
     });
 
     registerPopupEventHandler("popupshowing", function () {
       ok(false, "prompt showing");
     });
     registerPopupEventHandler("popupshown", function () {
       ok(false, "prompt shown");

--- a/dom/indexedDB/test/browser_quotaPromptAllow.js
+++ b/dom/indexedDB/test/browser_quotaPromptAllow.js
@@ -7,16 +7,17 @@
 const testPageURL = "http://bug704464-1.example.com/browser/" +
   "dom/indexedDB/test/browser_quotaPrompt.html";
 const notificationID = "indexedDB-quota-prompt";
 
 function test()
 {
   waitForExplicitFinish();
   requestLongerTimeout(10);
+  PopupNotifications.transitionsEnabled = false;
   removePermission(testPageURL, "indexedDB-unlimited");
   Services.prefs.setIntPref("dom.indexedDB.warningQuota", 2);
   executeSoon(test1);
 }
 
 let addMoreTest1Count = 0;
 
 function test1()
@@ -103,16 +104,17 @@ function test2()
             is(getPermission(testPageURL, "indexedDB-unlimited"),
                Components.interfaces.nsIPermissionManager.ALLOW_ACTION,
                "Correct permission set");
 
             gBrowser.removeCurrentTab();
             unregisterAllPopupEventHandlers();
             removePermission(testPageURL, "indexedDB");
             Services.prefs.clearUserPref("dom.indexedDB.warningQuota");
+            PopupNotifications.transitionsEnabled = true;
             executeSoon(finish);
           });
           executeSoon(function() { dispatchEvent("indexedDB-done"); });
         }
         else {
           ++addMoreCount;
           executeSoon(function() { dispatchEvent("indexedDB-addMore"); });
         }

--- a/dom/indexedDB/test/browser_quotaPromptDatabases.js
+++ b/dom/indexedDB/test/browser_quotaPromptDatabases.js
@@ -7,16 +7,17 @@
 const testPageURL = "http://bug704464-3.example.com/browser/" +
   "dom/indexedDB/test/browser_quotaPromptDatabases.html";
 const notificationID = "indexedDB-quota-prompt";
 
 function test()
 {
   waitForExplicitFinish();
   requestLongerTimeout(10);
+  PopupNotifications.transitionsEnabled = false;
   removePermission(testPageURL, "indexedDB-unlimited");
   Services.prefs.setIntPref("dom.indexedDB.warningQuota", 2);
   executeSoon(test1);
 }
 
 let addMoreTest1Count = 0;
 
 function test1()
@@ -38,16 +39,17 @@ function test1()
           setFinishedCallback(function(result) {
             is(result, "finished", "Got 'finished' result");
             is(getPermission(testPageURL, "indexedDB-unlimited"),
                Components.interfaces.nsIPermissionManager.ALLOW_ACTION,
                "Correct permission set");
             gBrowser.removeCurrentTab();
             unregisterAllPopupEventHandlers();
             addMoreTest1Count = seenPopupCount;
+            PopupNotifications.transitionsEnabled = true;
             executeSoon(finish);
           });
           executeSoon(function() { dispatchEvent("indexedDB-done"); });
         }
         else {
           ++addMoreTest1Count;
           executeSoon(function() { dispatchEvent("indexedDB-addMore"); });
         }

--- a/dom/indexedDB/test/browser_quotaPromptDelete.js
+++ b/dom/indexedDB/test/browser_quotaPromptDelete.js
@@ -7,16 +7,17 @@
 const testPageURL = "http://bug702292.example.com/browser/" +
   "dom/indexedDB/test/browser_quotaPromptDelete.html";
 const notificationID = "indexedDB-quota-prompt";
 
 function test()
 {
   waitForExplicitFinish();
   requestLongerTimeout(10);
+  PopupNotifications.transitionsEnabled = false;
   removePermission(testPageURL, "indexedDB-unlimited");
   Services.prefs.setIntPref("dom.indexedDB.warningQuota", 2);
   executeSoon(test1);
 }
 
 let addMoreTest1Count = 0;
 let haveReset = false;
 let secondTimeCount = 0;
@@ -49,16 +50,17 @@ function test1()
               } else {
                 setFinishedCallback(function(result) {
                   is(result, "finished", "Got 'finished' result");
                   is(getPermission(testPageURL, "indexedDB-unlimited"),
                      Components.interfaces.nsIPermissionManager.DENY_ACTION,
                      "Correct permission set");
                   gBrowser.removeCurrentTab();
                   unregisterAllPopupEventHandlers();
+                  PopupNotifications.transitionsEnabled = true;
                   executeSoon(finish);
                 });
                 executeSoon(function() { dispatchEvent("indexedDB-done"); });
               }
             }
 
             function secondTimeThroughAddMore() {
               setFinishedCallback(secondTimeThroughCallback);

--- a/dom/indexedDB/test/browser_quotaPromptDeny.js
+++ b/dom/indexedDB/test/browser_quotaPromptDeny.js
@@ -7,16 +7,17 @@
 const testPageURL = "http://bug704464-2.example.com/browser/" +
   "dom/indexedDB/test/browser_quotaPrompt.html";
 const notificationID = "indexedDB-quota-prompt";
 
 function test()
 {
   waitForExplicitFinish();
   requestLongerTimeout(10);
+  PopupNotifications.transitionsEnabled = false;
   removePermission(testPageURL, "indexedDB-unlimited");
   Services.prefs.setIntPref("dom.indexedDB.warningQuota", 2);
   executeSoon(test1);
 }
 
 let addMoreTest1Count = 0;
 
 function test1()
@@ -43,16 +44,17 @@ function test1()
           setFinishedCallback(function(result) {
             is(result, "finished", "Got 'finished' result");
             is(getPermission(testPageURL, "indexedDB-unlimited"),
                Components.interfaces.nsIPermissionManager.DENY_ACTION,
                "Correct permission set");
             gBrowser.removeCurrentTab();
             unregisterAllPopupEventHandlers();
             addMoreTest1Count = seenPopupCount;
+            PopupNotifications.transitionsEnabled = true;
             executeSoon(test2);
           });
           executeSoon(function() { dispatchEvent("indexedDB-done"); });
         }
         else {
           ++addMoreTest1Count;
           executeSoon(function() { dispatchEvent("indexedDB-addMore"); });
         }

--- a/toolkit/modules/PopupNotifications.jsm
+++ b/toolkit/modules/PopupNotifications.jsm
@@ -151,16 +151,30 @@ PopupNotifications.prototype = {
       iconBox.addEventListener("keypress", this, false);
     }
   },
   get iconBox() {
     return this._iconBox;
   },
 
   /**
+   * Enable or disable the opening/closing transition.
+   * @param state
+   *        Boolean state
+   */
+  set transitionsEnabled(state) {
+    if (state) {
+      this.panel.removeAttribute("animate");
+    }
+    else {
+      this.panel.setAttribute("animate", "false");
+    }
+  },
+
+  /**
    * Retrieve a Notification object associated with the browser/ID pair.
    * @param id
    *        The Notification ID to search for.
    * @param browser
    *        The browser whose notifications should be searched. If null, the
    *        currently selected browser's notifications will be searched.
    *
    * @returns the corresponding Notification object, or null if no such