Add customize toolbar context item to the menubar. Thanks to Stephen Walker for the patch.

mail/base/content/mailWindowOverlay.xul

@@ -1,5 +1,4 @@
 <?xml version="1.0"?>
-
 # The contents of this file are subject to the Netscape Public
 # License Version 1.1 (the "License"); you may not use this file
 # except in compliance with the License. You may obtain a copy of
@@ -968,7 +967,8 @@
 
 <toolbox id="mail-toolbox" class="toolbox-top" mode="icons">  
   <!-- Menu -->
-  <toolbar type="menubar" id="mail-toolbar-menubar" class="chromeclass-menubar" customizable="true" defaultset="menubar-items" mode="icons">
+  <toolbar type="menubar" id="mail-toolbar-menubar" class="chromeclass-menubar" customizable="true"
+           context="toolbar-context-menu" defaultset="menubar-items" mode="icons">
     <toolbaritem id="menubar-items" align="center">
       <menubar id="mail-menubar" style="border:0px;padding:0px;margin:0px;-moz-appearance:none">
         <!-- File -->

mail/components/addrbook/content/addressbook.xul

@@ -22,6 +22,7 @@
 #   Seth Spitzer <sspitzer@netscape.com>
 
 <?xml-stylesheet href="chrome://messenger/skin/addressbook/addressbook.css" type="text/css"?> 
+
 <?xul-overlay href="chrome://communicator/content/contentAreaContextOverlay.xul"?>
 
 <!DOCTYPE window [
@@ -146,7 +147,7 @@
 
 <toolbox id="ab-toolbox" class="toolbox-top" mode="icons">
   <toolbar type="menubar" id="addrbook-toolbar-menubar" class="chromeclass-menubar" customizable="true"
-     defaultset="menubar-items" mode="icons">
+           context="toolbar-context-menu" defaultset="menubar-items" mode="icons">
 
    <toolbaritem id="menubar-items" align="center">
      <menubar id="mail-menubar" style="border:0px;padding:0px;margin:0px;-moz-appearance:none">

mail/components/compose/content/messengercompose.xul

@@ -221,7 +221,7 @@
   <!-- Menu -->
   <!-- if you change the id of the menubar, be sure to update mailCore.js::CustomizeMailToolbar and MailToolboxCustomizeDone -->
   <toolbar type="menubar" id="compose-toolbar-menubar" class="chromeclass-menubar" customizable="true"
-     defaultset="menubar-items" mode="full">
+           context="toolbar-context-menu" defaultset="menubar-items" mode="full">
 
      <toolbaritem id="menubar-items" align="center">
       <menubar id="mail-menubar" style="border:0px;padding:0px;margin:0px;-moz-appearance:none">