→ (is-a?/c menu%) label : label-string?
(or/c (is-a?/c menu%) (is-a?/c popup-menu%) (is-a?/c menu-bar%)) help-string : (or/c label-string? #f) = #f
demand-callback : ((is-a?/c menu%) . -> . any) = (lambda (m) (void))
Creates a new menu with the given label.
If help-string is not #f, the menu has a help string. See get-help-string for more information.
The demand-callback procedure is called by the default on-demand method with the object itself.