bug#500: GTK Emacs stops reacting to keyboard events after cancelling menu by hitting Escape

[Chong Yidong]

Hi Jan,

Could you take a look at this?

> 0) Make sure you run GTK Emacs and the main menu is on.
>
> 1) Click on any main menu item. The drop-down menu with child items
>    will appear.
>
> 2) Move mouse down so it is over one of the child items (but not
>    separator).
>
> 3) Hit Escape to cancel the menu. The menu will disappear (it is the
>    expected behavior).
>
> 4) Press any key. Nothing happens.
>
> 5) Click on Emacs buffer. Nothing happens. Emacs looks frozen.
>
> To workaround:
>
> Click on any main menu item and hit Escape *immediately*. Emacs is
> back to life.