mouse-autoselect-window with menu pane

[Marshall, Simon]

Hi Martin, thanks again for the implementation, but a small buggette...

src/emacs -Q
(setq mouse-autoselect-window 3) C-x C-e C-x 2

And select the lower window.  Move quickly from the lower window up to the
menu bar and select the Help menu.  While holding down mouse-1, move quickly
to the upper window (ie, but off the Help menu pane).  Wait until the
autoselect timeout has occurred and release mouse-1.  Selection of the upper
window occurs (presumably it occurred while mouse-1 was down but there was
no redisplay at that time), rather than selection remaining in the lower
window.  Selection only seems to happen if the mouse is outside the menu
pane when the autoselect timeout occurs.

While this might seem fairly innocuous, it bites in the more frequent
situation where you momentarily leave the menu pane before returning to
select an entry.  So, instead of releasing mouse-1 after the autoselect
timeout, move back into the Help menu pane and select About Emacs.  The
action occurs in the upper window, not the lower window which was selected
when you opened the Help menu.

So, it seems that by being outside the menu pane when the autoselect timeout
occurs, autoselection is performed.  I think it is sensible to suppress
autoselection in this case (ie, reschedule the delay).

Occurs with Lucid/Motif toolkit, Solaris 2.8, displayed on PC via Exceed
server.  Also occurs if you open the Help menu with a single mouse-1 click,
rather than holding down mouse-1.

Simon.