disabling edit menu items during modal dialogs

[wilcox@cmns.think.com]

I have an application which adds a few menu items to the edit menu.
The application also makes use of several modal dialogs, to which
these new menu items do not apply. Currently I define a method which
makes them beep when they are called from a modal-dialog. However, I
would prefer to disable them instead. Is this possible?

I would even settle for disabling the entire edit menu while the
modal-dialog is up, but my attempt to do this did not work:

(defmacro without-edit-menu (&body body)
  `(progn
     (menu-disable *edit-menu*)
     (let ((value (progn ,@body)))
       (menu-enable *edit-menu*)
       (values value)
       )))