Humm....... you want to hide it in Design View whilst working on the rest of the site?
If that is the case set the menu container <div> to display: none; -
<div id="menu" style="display: none;">This is the content menu</div>
Then either set it to display: block; when you're ready to view it live or remove the style completely.
Do that in a DESIGN TIME STYLESHEET in DW. That will hide the stuff in Design view without having to modify any of the code.