--- a/browser/components/customizableui/src/CustomizableUI.jsm
+++ b/browser/components/customizableui/src/CustomizableUI.jsm
@@ -24,17 +24,16 @@ XPCOMUtils.defineLazyGetter(this, "gWidg
 XPCOMUtils.defineLazyServiceGetter(this, "gELS",
   "@mozilla.org/eventlistenerservice;1", "nsIEventListenerService");
 
 const kNSXUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 const kSpecialWidgetPfx = "customizableui-special-";
 
 const kCustomizationContextMenu = "customizationContextMenu";
-const kContextMenuBackup        = "customization-old-context";
 
 
 const kPrefCustomizationState        = "browser.uiCustomization.state";
 const kPrefCustomizationAutoAdd      = "browser.uiCustomization.autoAdd";
 const kPrefCustomizationDebug        = "browser.uiCustomization.debug";
 
 /**
  * The keys are the handlers that are fired when the event type (the value)
@@ -398,32 +397,25 @@ let CustomizableUIInternal = {
     gELS.removeSystemEventListener(aPanel, "keypress", this, false);
     let win = aPanel.ownerDocument.defaultView;
     let panels = gPanelsForWindow.get(win);
     if (panels) {
       panels.delete(this._getPanelForNode(aPanel));
     }
   },
 
-  ensureButtonContextMenu: function(aNode, ourContextMenu) {
-    if (ourContextMenu) {
-      let currentCtxt = aNode.getAttribute("context");
-      // Need to save widget's own context menu if we're replacing it:
-      if (currentCtxt && currentCtxt != kCustomizationContextMenu) {
-        aNode.setAttribute(kContextMenuBackup, currentCtxt);
-      }
-      aNode.setAttribute("context", kCustomizationContextMenu);
-    } else if (aNode.getAttribute("context") == kCustomizationContextMenu) {
-      let oldCtxt = aNode.getAttribute(kContextMenuBackup);
-      if (oldCtxt) {
-        aNode.setAttribute("context", oldCtxt);
-        aNode.removeAttribute(kContextMenuBackup);
-      } else {
+  ensureButtonContextMenu: function(aNode, aShouldHaveCustomizationMenu) {
+    let currentContextMenu = aNode.getAttribute("context") ||
+                             aNode.getAttribute("contextmenu");
+    if (aShouldHaveCustomizationMenu) {
+      if (!currentContextMenu)
+        aNode.setAttribute("context", kCustomizationContextMenu);
+    } else {
+      if (currentContextMenu == kCustomizationContextMenu)
         aNode.removeAttribute("context");
-      }
     }
   },
 
   getWidgetProvider: function(aWidgetId) {
     if (this.isSpecialWidget(aWidgetId)) {
       return CustomizableUI.PROVIDER_SPECIAL;
     }
     if (gPalette.has(aWidgetId)) {