add an id to the help menu item separator.

mail/base/content/mailWindowOverlay.xul

@@ -1517,10 +1517,10 @@
         <menupopup id="menu_HelpPopup">
           <menuitem accesskey="&releaseCmd.accesskey;" label="&releaseCmd.label;" oncommand="loadThrobberUrl('mailnews.release_notes.url');"/>
           <menuitem accesskey="&hintsAndTips.accesskey;" label="&hintsAndTips.label;" oncommand="loadThrobberUrl('mailnews.hints_and_tips.url');"/>
-          <menuseparator/>
-            <menuitem id="aboutName" accesskey="&aboutCmd.accesskey;"
-                      label="&aboutCmd.label;"
-                      oncommand="window.openDialog('chrome://messenger/content/aboutDialog.xul', 'About', 'modal,centerscreen,chrome,resizable=no');"/>
+          <menuseparator id="menu_HelpAboutSeparator"/>
+          <menuitem id="aboutName" accesskey="&aboutCmd.accesskey;"
+                    label="&aboutCmd.label;"
+                    oncommand="window.openDialog('chrome://messenger/content/aboutDialog.xul', 'About', 'modal,centerscreen,chrome,resizable=no');"/>
         </menupopup>
       </menu>
       <spacer flex="100%"/>

mail/components/addrbook/content/addressbook.xul

@@ -366,7 +366,7 @@
           <menupopup id="menu_HelpPopup">
             <menuitem accesskey="&releaseCmd.accesskey;" label="&releaseCmd.label;" oncommand="loadThrobberUrl('mailnews.release_notes.url');"/>
             <menuitem accesskey="&hintsAndTips.accesskey;" label="&hintsAndTips.label;" oncommand="loadThrobberUrl('mailnews.hints_and_tips.url');"/>
-            <menuseparator/>
+            <menuseparator id="menu_HelpAboutSeparator"/>
             <menuitem id="aboutName" accesskey="&aboutCmd.accesskey;"
                       label="&aboutCmd.label;"
                       oncommand="window.openDialog('chrome://messenger/content/aboutDialog.xul', 'About', 'modal,centerscreen,chrome,resizable=no');"/>

mail/components/compose/content/messengercompose.xul

@@ -430,7 +430,7 @@
         <menupopup id="menu_HelpPopup">
           <menuitem accesskey="&releaseCmd.accesskey;" label="&releaseCmd.label;" oncommand="loadThrobberUrl('mailnews.release_notes.url');"/>
           <menuitem accesskey="&hintsAndTips.accesskey;" label="&hintsAndTips.label;" oncommand="loadThrobberUrl('mailnews.hints_and_tips.url');"/>
-          <menuseparator/>
+          <menuseparator id="menu_HelpAboutSeparator"/>
           <menuitem id="aboutName" accesskey="&aboutCmd.accesskey;"
                     label="&aboutCmd.label;"
                     oncommand="window.openDialog('chrome://messenger/content/aboutDialog.xul', 'About', 'modal,centerscreen,chrome,resizable=no');"/>