issue 449 - override toolbar icon context menu if left click action is redefined

lib/ui.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 1069 matching lines @@
     if (icon.localName == "statusbarpanel")
     {
       if (Prefs.defaultstatusbaraction == 0)
         icon.setAttribute("popup", icon.getAttribute("context"));
       else
         icon.removeAttribute("popup");
     }
     else
     {
       if (Prefs.defaulttoolbaraction == 0)
+      {
         icon.setAttribute("type", "menu");
+        icon.removeAttribute("context");
+      }
       else
+      {
         icon.setAttribute("type", "menu-button");
+        icon.setAttribute("context", "abp-status-popup");
+      }
     }
 
     icon.setAttribute("abpstate", state);
   },
 
   /**
    * Shows or hides status bar icons in all windows, according to pref.
    */
   updateStatusbarIcon: function(/**Window*/ window)
   {
@@ skipping 817 matching lines @@
   ["abp-command-contribute", "command", UI.openContributePage.bind(UI)],
   ["abp-command-contribute-hide", "command", UI.hideContributeButton.bind(UI)]
 ];
 
 onShutdown.add(function()
 {
   for (let window in UI.applicationWindows)
     if (UI.isBottombarOpen(window))
       UI.toggleBottombar(window);
 });