A menu-bar% object is created for a particular frame% object. A frame can have at most one menu bar; an exn:fail:contract exception is raised when a new menu bar is created for a frame that already has a menu bar.
Creates a menu bar in the specified frame. The menu bar is initially empty. If 'root is supplied as parent, the menu bar becomes active only when no other frames are shown. A 'root parent is allowed only when current-eventspace-has-menu-root? returns #t, and only if no such menu bar has been created before, otherwise an exn:fail:contract exception is raised.
The demand-callback procedure is called by the default on-demand method with the object itself.
Enables or disables the menu bar (i.e., all of its menus). Each menu’s is-enabled? method returns #f only if the menu is specifically disabled (in addition to the menu bar).
Returns the menu bar’s frame, or returns 'root if the menu bar is shown when no other frames are shown.
Returns #t if the menu bar is enabled, #f otherwise.