bug#7464: 24.0.50; mouse highlighting vanishes upon unsplitting window

[Eli Zaretskii <eliz@gnu.org>]

> Date: 31 Mar 2012 01:09:26 +0200
> From: "Stephen Berman" <stephen.berman@gmx.net>
> Cc: cyd@gnu.org, 7464@debbugs.gnu.org
> 
> But when I set the breakpoint with GTK scrollbars enabled, execution
> stops many times:
> 
> Breakpoint 19, cancel_mouse_face (f=0x87349c8)
>     at /data/steve/bzr/emacs/quickfixes/src/xdisp.c:27545
> 27545     Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (f);
> (gdb) c
> Continuing.
> 
> At each break, a portion of the scroll bar is redisplayed.  For example,
> after typing C-x 2, execution stops and the scroll bar vanishes.  When I
> type c, the upper portion is redisplayed, then execution stops.  Next c,
> the upper scroll bar vanishes but the lower one is redisplayed, then
> execution stops.  Then the upper scroll bar is redisplayed again,
> completing the window splitting, and the execution returns to the
> command loop.  However, throughout this process, as long as the mouse
> pointer remains over the mouse-face propertized text, it remains
> highlighted.  Likewise after Fdelete_other_windows_internal.

Can you show a backtrace in a few instances when the breakpoint inside
cancel_mouse_face breaks?  I think these calls are those that keep the
highlighting from being wiped out in the GTK build.