--- a/toolkit/content/tests/widgets/test_videocontrols.html
+++ b/toolkit/content/tests/widgets/test_videocontrols.html
@@ -83,42 +83,50 @@ function runTest(event) {
      */
     case 1:
       // Check initial state upon load
       is(event.type, "canplaythrough", "checking event type");
       is(video.paused, true, "checking video play state");
       is(video.muted, false, "checking video mute state");
 
       // Click the play button
-      synthesizeMouse(video, playButtonCenterX, playButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, playButtonCenterX, playButtonCenterY, { });
+      });
       break;
 
     case 2:
       is(event.type, "play",  "checking event type");
       is(video.paused, false, "checking video play state");
       is(video.muted, false,  "checking video mute state");
 
       // Click the pause button
-      synthesizeMouse(video, playButtonCenterX, playButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, playButtonCenterX, playButtonCenterY, { });
+      });
       break;
 
     case 3:
       is(event.type, "pause", "checking event type");
       is(video.paused, true,  "checking video play state");
       is(video.muted, false,  "checking video mute state");
 
-      synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { }); // Mute.
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { }); // Mute.
+      });
       break;
 
     case 4:
       is(event.type, "volumechange", "checking event type");
       is(video.paused, true,  "checking video play state");
       is(video.muted,  true,  "checking video mute state");
 
-      synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { }); // Unmute.
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { }); // Unmute.
+      });
       break;
 
     /*
      * Bug 470596: Make sure that having CSS border or padding doesn't
      * break the controls (though it should move them)
      */
     case 5:
       is(event.type, "volumechange", "checking event type");
@@ -126,33 +134,37 @@ function runTest(event) {
       is(video.muted,  false, "checking video mute state");
 
       video.style.border = "medium solid purple";
       video.style.borderWidth = "30px 40px 50px 60px";
       video.style.padding = "10px 20px 30px 40px";
       // totals: top: 40px, right: 60px, bottom: 80px, left: 100px
 
       // Click the play button
-      synthesizeMouse(video, 100 + playButtonCenterX, 40 + playButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, 100 + playButtonCenterX, 40 + playButtonCenterY, { });
+      });
       break;
 
     case 6:
       is(event.type, "play",  "checking event type");
       is(video.paused, false, "checking video play state");
       is(video.muted, false,  "checking video mute state");
       video.pause();
       break;
 
     case 7:
       is(event.type, "pause",  "checking event type");
       is(video.paused, true, "checking video play state");
       is(video.muted, false,  "checking video mute state");
 
       // Click the mute button
-      synthesizeMouse(video, 100 + muteButtonCenterX, 40 + muteButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, 100 + muteButtonCenterX, 40 + muteButtonCenterY, { });
+      });
       break;
 
     case 8:
       is(event.type, "volumechange", "checking event type");
       is(video.paused, true,  "checking video play state");
       is(video.muted,  true,  "checking video mute state");
       // Clear the style set in test 5.
       video.style.border = "";
@@ -182,38 +194,42 @@ function runTest(event) {
      * Drag the slider's thumb to the halfway point with the mouse.
      */
     case 11:
       is(event.type, "seeked", "checking event type");
       ok(true, "video position is at " + video.currentTime);
       // Bug 477434 -- sometimes we get 0.098999 here instead of 0!
       // is(video.currentTime, 0.0, "checking playback position");
 
-      var beginDragX = scrubberOffsetX;
-      var endDragX = scrubberOffsetX + (scrubberWidth / 2);
-      synthesizeMouse(video, beginDragX, scrubberCenterY, { type: "mousedown", button: 0 });
-      synthesizeMouse(video, endDragX,   scrubberCenterY, { type: "mousemove", button: 0 });
-      synthesizeMouse(video, endDragX,   scrubberCenterY, { type: "mouseup",   button: 0 });
+      SimpleTest.executeSoon(() => {
+        var beginDragX = scrubberOffsetX;
+        var endDragX = scrubberOffsetX + (scrubberWidth / 2);
+        synthesizeMouse(video, beginDragX, scrubberCenterY, { type: "mousedown", button: 0 });
+        synthesizeMouse(video, endDragX,   scrubberCenterY, { type: "mousemove", button: 0 });
+        synthesizeMouse(video, endDragX,   scrubberCenterY, { type: "mouseup",   button: 0 });
+      });
       break;
 
     case 12:
       is(event.type, "seeking", "checking event type");
       ok(true, "video position is at " + video.currentTime);
       break;
 
     /*
      * Click the slider at the 1/4 point with the mouse (jump backwards)
      */
     case 13:
       is(event.type, "seeked", "checking event type");
       ok(true, "video position is at " + video.currentTime);
       var expectedTime = videoDuration / 2;
       ok(Math.abs(video.currentTime - expectedTime) < 0.1, "checking expected playback position");
 
-      synthesizeMouse(video, scrubberOffsetX + (scrubberWidth / 4), scrubberCenterY, { });
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, scrubberOffsetX + (scrubberWidth / 4), scrubberCenterY, { });
+      });
       break;
 
     case 14:
       is(event.type, "seeking", "checking event type");
       ok(true, "video position is at " + video.currentTime);
       break;
 
     case 15:
@@ -234,80 +250,90 @@ function runTest(event) {
 
     // See bug 694696.
     case 16:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0.1, "Volume should be set.");
       ok(!video.muted, "Video is not muted.");
 
       video.focus();
-      synthesizeKey("VK_DOWN", {});
+      SimpleTest.executeSoon(() => synthesizeKey("VK_DOWN", {}));
       break;
 
     case 17:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0, "Volume should be 0.");
       ok(!video.muted, "Video is not muted.");
-      ok(isMuteButtonMuted(), "Mute button says it's muted");
 
-      synthesizeKey("VK_UP", {});
+      SimpleTest.executeSoon(() => {
+        ok(isMuteButtonMuted(), "Mute button says it's muted");
+        synthesizeKey("VK_UP", {});
+      });
       break;
 
     case 18:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0.1, "Volume is increased.");
       ok(!video.muted, "Video is not muted.");
-      ok(!isMuteButtonMuted(), "Mute button says it's not muted");
 
-      synthesizeKey("VK_DOWN", {});
+      SimpleTest.executeSoon(() => {
+        ok(!isMuteButtonMuted(), "Mute button says it's not muted");
+        synthesizeKey("VK_DOWN", {});
+      });
       break;
 
     case 19:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0, "Volume should be 0.");
       ok(!video.muted, "Video is not muted.");
-      ok(isMuteButtonMuted(), "Mute button says it's muted");
 
-      synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        ok(isMuteButtonMuted(), "Mute button says it's muted");
+        synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { });
+      });
       break;
 
     case 20:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0.5, "Volume should be 0.5.");
       ok(!video.muted, "Video is not muted.");
 
-      synthesizeKey("VK_UP", {});
+      SimpleTest.executeSoon(() => synthesizeKey("VK_UP", {}));
       break;
 
     case 21:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0.6, "Volume should be 0.6.");
       ok(!video.muted, "Video is not muted.");
 
-      synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { });
+      });
       break;
 
     case 22:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0.6, "Volume should be 0.6.");
       ok(video.muted, "Video is muted.");
 
-      ok(isMuteButtonMuted(), "Mute button says it's muted");
-
-      synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        ok(isMuteButtonMuted(), "Mute button says it's muted");
+        synthesizeMouse(video, muteButtonCenterX, muteButtonCenterY, { });
+      });
       break;
 
     case 23:
       is(event.type, "volumechange", "checking event type");
       is(video.volume, 0.6, "Volume should be 0.6.");
       ok(!video.muted, "Video is not muted.");
 
-      ok(!isMuteButtonMuted(), "Mute button says it's not muted");
-
-      synthesizeMouse(video, fullscreenButtonCenterX, fullscreenButtonCenterY, { });
+      SimpleTest.executeSoon(() => {
+        ok(!isMuteButtonMuted(), "Mute button says it's not muted");
+        synthesizeMouse(video, fullscreenButtonCenterX, fullscreenButtonCenterY, { });
+      });
       break;
 
     case 24:
       is(event.type, "mozfullscreenchange", "checking event type");
       is(video.volume, 0.6, "Volume should still be 0.6");
       SimpleTest.executeSoon(function() {
         isVolumeSliderShowingCorrectVolume(video.volume);
         synthesizeKey("VK_ESCAPE", {});

--- a/toolkit/content/tests/widgets/test_videocontrols_audio.html
+++ b/toolkit/content/tests/widgets/test_videocontrols_audio.html
@@ -32,19 +32,21 @@
       if (result) {
         return result;
       }
     }
     return false;
   }
 
   function loadedmetadata(event) {
-    var controlBar = findElementByAttribute(video, "class", "controlBar");
-    is(controlBar.getAttribute("fullscreen-unavailable"), "true", "Fullscreen button is hidden");
-    SimpleTest.finish();
+    SimpleTest.executeSoon(function() {
+      var controlBar = findElementByAttribute(video, "class", "controlBar");
+      is(controlBar.getAttribute("fullscreen-unavailable"), "true", "Fullscreen button is hidden");
+      SimpleTest.finish();
+    });
   }
 
   var video = document.getElementById("video");
 
   SpecialPowers.pushPrefEnv({"set": [["media.cache_size", 40000]]}, startTest);
   function startTest() {
     // Kick off test once audio has loaded.
     video.addEventListener("loadedmetadata", loadedmetadata, false);

--- a/toolkit/content/widgets/videocontrols.xml
+++ b/toolkit/content/widgets/videocontrols.xml
@@ -626,18 +626,22 @@
                             // Nothing to do...
                             break;
                         default:
                             this.log("!!! event " + aEvent.type + " not handled!");
                     }
                 },
 
                 terminateEventListeners : function () {
-                    for (let event of this.videoEvents)
-                        this.video.removeEventListener(event, this, false);
+                    for (let event of this.videoEvents) {
+                        this.video.removeEventListener(event, this, {
+                            capture: true,
+                            mozSystemGroup: true
+                        });
+                    }
 
                     for (let element of this.controlListeners) {
                         element.item.removeEventListener(element.event, element.func,
                                                          { mozSystemGroup: true });
                     }
 
                     delete this.controlListeners;
 
@@ -1323,20 +1327,25 @@
                     this.fullscreenButton   = document.getAnonymousElementByAttribute(binding, "class", "fullscreenButton");
                     this.volumeForeground   = document.getAnonymousElementByAttribute(binding, "anonid", "volumeForeground");
 
                     this.isAudioOnly = (this.video instanceof HTMLAudioElement);
                     this.setupInitialState();
                     this.setupNewLoadState();
 
                     // Use the handleEvent() callback for all media events.
-                    // The "error" event listener must capture, so that it can trap error events
-                    // from the <source> children, which don't bubble.
-                    for (let event of this.videoEvents)
-                        this.video.addEventListener(event, this, (event == "error") ? true : false);
+                    // Only the "error" event listener must capture, so that it can trap error
+                    // events from <source> children, which don't bubble. But we use capture
+                    // for all events in order to simplify the event listener add/remove.
+                    for (let event of this.videoEvents) {
+                        this.video.addEventListener(event, this, {
+                            capture: true,
+                            mozSystemGroup: true
+                        });
+                    }
 
                     var self = this;
 
                     this.controlListeners = [];
 
                     // Helper function to add an event listener to the given element
                     function addListener(elem, eventName, func) {
                       let boundFunc = func.bind(self);
@@ -1662,17 +1671,17 @@
           this.randomID = 0;
           this.Utils = {
             randomID : 0,
             videoEvents : ["play",
                            "playing"],
             controlListeners: [],
             terminateEventListeners : function () {
               for (let event of this.videoEvents)
-                this.video.removeEventListener(event, this, false);
+                this.video.removeEventListener(event, this, { mozSystemGroup: true });
 
               for (let element of this.controlListeners) {
                 element.item.removeEventListener(element.event, element.func,
                                                  { mozSystemGroup: true });
               }
 
               delete this.controlListeners;
             },
@@ -1737,17 +1746,17 @@
                 let boundFunc = func.bind(self);
                 self.controlListeners.push({ item: elem, event: eventName, func: boundFunc });
                 elem.addEventListener(eventName, boundFunc, { mozSystemGroup: true });
               }
               addListener(this.clickToPlay, "click", this.clickToPlayClickHandler);
               addListener(this.video, "MozNoControlsBlockedVideo", this.blockedVideoHandler);
 
               for (let event of this.videoEvents) {
-                this.video.addEventListener(event, this, false);
+                this.video.addEventListener(event, this, { mozSystemGroup: true });
               }
 
               if (this.video.autoplay && !this.video.mozAutoplayEnabled) {
                 this.blockedVideoHandler();
               }
             }
           };
           this.Utils.init(this);