diff --git a/browser/base/content/browser-fullZoom.js b/browser/base/content/browser-fullZoom.js
index 32d9e05c693..fd26ffad5f4 100644
--- a/browser/base/content/browser-fullZoom.js
+++ b/browser/base/content/browser-fullZoom.js
@@ -510,14 +510,14 @@ var FullZoom = {
   },
 
   /**
-   * Asynchronously broadcasts "FullZoom:TESTS:location-change" so that tests
-   * can select tabs, load pages, etc. and be notified when the zoom levels on
-   * those pages change.  The notification is always asynchronous so that
-   * observers are guaranteed a consistent behavior.
+   * Asynchronously broadcasts "browser-fullZoom:location-change" so that
+   * listeners can be notified when the zoom levels on those pages change.
+   * The notification is always asynchronous so that observers are guaranteed a
+   * consistent behavior.
    */
   _notifyOnLocationChange: function FullZoom__notifyOnLocationChange() {
     this._executeSoon(function () {
-      Services.obs.notifyObservers(null, "FullZoom:TESTS:location-change", "");
+      Services.obs.notifyObservers(null, "browser-fullZoom:location-change", "");
     });
   },
 
diff --git a/browser/base/content/test/general/head.js b/browser/base/content/test/general/head.js
index 3f3702ec382..524265791b0 100644
--- a/browser/base/content/test/general/head.js
+++ b/browser/base/content/test/general/head.js
@@ -317,7 +317,7 @@ let FullZoomHelper = {
     Services.obs.addObserver(function obs(subj, topic, data) {
       Services.obs.removeObserver(obs, topic);
       deferred.resolve();
-    }, "FullZoom:TESTS:location-change", false);
+    }, "browser-fullZoom:location-change", false);
     return deferred.promise;
   },
 
diff --git a/browser/components/customizableui/src/CustomizableWidgets.jsm b/browser/components/customizableui/src/CustomizableWidgets.jsm
index 927f6a4335d..8a0b720dd6a 100644
--- a/browser/components/customizableui/src/CustomizableWidgets.jsm
+++ b/browser/components/customizableui/src/CustomizableWidgets.jsm
@@ -376,6 +376,7 @@ const CustomizableWidgets = [{
       // Register ourselves with the service so we know when the zoom prefs change.
       Services.obs.addObserver(updateZoomResetButton, "browser-fullZoom:zoomChange", false);
       Services.obs.addObserver(updateZoomResetButton, "browser-fullZoom:zoomReset", false);
+      Services.obs.addObserver(updateZoomResetButton, "browser-fullZoom:location-change", false);
 
       if (inPanel) {
         let panel = aDocument.getElementById(kPanelId);
@@ -446,6 +447,7 @@ const CustomizableWidgets = [{
           CustomizableUI.removeListener(listener);
           Services.obs.removeObserver(updateZoomResetButton, "browser-fullZoom:zoomChange");
           Services.obs.removeObserver(updateZoomResetButton, "browser-fullZoom:zoomReset");
+          Services.obs.removeObserver(updateZoomResetButton, "browser-fullZoom:location-change");
           let panel = aDoc.getElementById(kPanelId);
           panel.removeEventListener("popupshowing", updateZoomResetButton);
           let container = aDoc.defaultView.gBrowser.tabContainer;
diff --git a/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_zoomrestore.js b/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_zoomrestore.js
index 2b8a2885bae..a2f0c6d2d58 100644
--- a/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_zoomrestore.js
+++ b/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_zoomrestore.js
@@ -14,7 +14,7 @@ function test() {
   function doTestWhenReady(aIsZoomedWindow, aWindow, aCallback) {
     // Need to wait on two things, the ordering of which is not guaranteed:
     // (1) the page load, and (2) FullZoom's update to the new page's zoom
-    // level.  FullZoom broadcasts "FullZoom:TESTS:location-change" when its
+    // level.  FullZoom broadcasts "browser-fullZoom:location-change" when its
     // update is done.  (See bug 856366 for details.)
 
     let n = 0;
@@ -30,7 +30,7 @@ function test() {
       Services.obs.removeObserver(onLocationChange, topic);
       if (++n == 2)
         doTest(aIsZoomedWindow, aWindow, aCallback);
-    }, "FullZoom:TESTS:location-change", false);
+    }, "browser-fullZoom:location-change", false);
 
     browser.loadURI("about:blank");
   }