Bug 631954 - Right-clicking on back button menu item opens additional back button menu. r=gavin

browser/base/content/browser.js

@@ -306,22 +306,28 @@ function SetClickAndHoldHandlers() {
     aElm.addEventListener("click", clickHandler, true);
   }
 
-  // Bug 414797: Clone the dropmarker's menu into both the back and
-  // the forward buttons.
+  // Bug 414797: Clone unified-back-forward-button's context menu into both the
+  // back and the forward buttons.
   var unifiedButton = document.getElementById("unified-back-forward-button");
   if (unifiedButton && !unifiedButton._clickHandlersAttached) {
-    var popup = document.getElementById("backForwardMenu").cloneNode(true);
+    unifiedButton._clickHandlersAttached = true;
+
+    let popup = document.getElementById("backForwardMenu").cloneNode(true);
     popup.removeAttribute("id");
-    var backButton = document.getElementById("back-button");
+    // Prevent the context attribute on unified-back-forward-button from being
+    // inherited.
+    popup.setAttribute("context", "");
+
+    let backButton = document.getElementById("back-button");
     backButton.setAttribute("type", "menu");
     backButton.appendChild(popup);
     _addClickAndHoldListenersOnElement(backButton);
-    var forwardButton = document.getElementById("forward-button");
+
+    let forwardButton = document.getElementById("forward-button");
     popup = popup.cloneNode(true);
     forwardButton.setAttribute("type", "menu");
     forwardButton.appendChild(popup);
     _addClickAndHoldListenersOnElement(forwardButton);
-    unifiedButton._clickHandlersAttached = true;
   }
 }