bug#18649: 25.0.50; Closing TTY menus on MS-Windows

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 7 Oct 2014 08:50:39 +0200
> From: Dani Moncayo <dmoncayo@gmail.com>
> 
> Recipe:
>   emacs -Q -nw
>   F10 C-g
> 
> C-g should close/exit the TTY menu, but it doesn't.
> 
> If I start to type something, the TTY menu dissapears, but the cursor is
> not visible anymore.

There's nothing wrong with TTY menus: ESC ESC ESC still pops the menu
down, as does clicking the mouse somewhere outside the menu.

The problem is with C-g: it somehow shortcuts too much, and bypasses
the code that was supposed to be seen by the menu displaying
functions.  For example, try "C-h k C-g": all you will see is "Quit"
in the echo area, but no help.  IOW, we throw to top level too early
or too radically.

I don't see this on GNU/Linux, probably again because the low-level
details of keyboard input are different.

The problem started somewhere between trunk revisions 117575 and
117589.  I have trunk binaries from these two revisions, and the
former still works correctly.  Unfortunately, this range of revisions
includes the jumbo changeset related to pixel-wise resizing, which at
the very least makes it easy to drown in the flood and miss the
important parts.

If someone has time to bisect more accurately, or debug this, or even
give an idea where to look, you are welcome.