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

chrome/content/ui/overlay.xul

 <?xml version="1.0"?>
 
 <!--
   - 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.
   -
@@ skipping 83 matching lines @@
     <command id="abp-command-toggleshowinstatusbar"/>
     <command id="abp-command-enable" oncommand="//"/>
     <command id="abp-command-contribute"/>
     <command id="abp-command-contribute-hide"/>
   </commandset>
 
   <statusbarpanel id="abp-status" class="statusbarpanel-iconic"
       context="abp-status-popup" tooltip="abp-tooltip"/>
 
   <toolbarbutton id="abp-toolbarbutton" class="toolbarbutton-1" label="&toolbarbutton.label;"
-      tooltip="abp-tooltip" context="abp-status-popup"/>
+      tooltip="abp-tooltip"/>
 
   <!-- Tools menu -->
   <menu id="abp-menuitem" label="&toolbarbutton.label;"/>
 
   <!-- Bottom bar -->
   <hbox id="abp-bottombar-container">
     <splitter id="abp-bottombar-splitter"/>
     <vbox id="abp-bottombar">
       <toolbox id="abp-bottombar-header">
         <toolbar id="abp-bottombar-toolbar" align="center" grippyhidden="true" fullscreentoolbar="true">
@@ skipping 10 matching lines @@
     xmlns:html="http://www.w3.org/1999/xhtml">
     <label id="abp-notification-title" class="header"/>
     <html:p id="abp-notification-message"/>
     <hbox id="abp-notification-question">
       <button id="abp-notification-yes" label="&notification.button.yes;"/>
       <button id="abp-notification-no" label="&notification.button.no;"/>
       <toolbarbutton id="abp-notification-close" label="&notification.button.close;"></toolbarbutton>
     </hbox>
   </panel>
 </overlay>