pjs/mailnews/base/resources/content/mailEditorOverlay.xul

<?xml version="1.0"?>

<!-- retrieve generic commands -->
<?xul-overlay href="chrome://messenger/content/mailOverlay.xul"?>

<!DOCTYPE window SYSTEM "chrome://messenger/locale/mailEditorOverlay.dtd" >

<overlay id="mailEditorOverlay"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

  <!-- editor specific UI items -->
  <menupopup id="menu_NewPopup">
    <!-- Command nodes and implemention are in mailOverlay.xul -->
    <menuitem id="menu_newMessage" position="2"/>
    <menuitem id="menu_newCard" position="3"/>
  </menupopup>

  <menupopup id="menu_FilePopup">
    <!-- The command node cmd_editSendPage is in editorOverlay.xul. 
         Implementation is in ComposerCommands.js
    -->
    <menuitem id="menu_sendPage" label="&sendPage.label;" accesskey="&sendPage.accesskey;" observes="cmd_editSendPage" insertafter="previewInBrowser"/>
  </menupopup>

</overlay>