
Nailmenus

Trivial system:

All windows with title bars opened as submenus get a 'tack it up' icon.
When clicked upon, the rest of the menu tree closes, leaving a nailed window.
Wimp_CreateSubMenu will not work until a Wimp_CreateMenu has been performed.
Wimp_CreateMenu will cause the tack-up window to be closed, and a menu_closed to be sent to the relevant task.
The tacked-up window remains held up until untacked or closed by the application.

