Re: Bug in incremental undrawing of mouseover highlighting

[Eli Zaretskii <eliz@gnu.org>]

> Cc: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>,
> 	  rogers-emacs@rgrjr.dyndns.org,  emacs-devel@gnu.org
> From: Chong Yidong <cyd@stupidchicken.com>
> Date: Sat, 25 Nov 2006 11:18:14 -0500
> 
> > I don't consider myself much of a redisplay expert, but I did express
> > a (different) concern for the patch as posted, a concern that
> > seemingly had no effect whatsoever.
> 
> It's still unclear, from the messages you sent, whether this bug can
> happen outside of HAVE_WINDOW_SYSTEM.  The bugfix is meant to plug a
> loophole in the code in note_mouse_highlight that computes whether or
> not the mouse highlight has been updated, which is only present for
> HAVE_WINDOW_SYSTEM.

You will see that the same code is duplicated, more or less, in
msdos.c, beginning at line 1612.  That is why I thought the same
problem could happen there, and that is why I was bothered by the fact
that the fix was only applied to builds that define
HAVE_WINDOW_SYSTEM.

Meanwhile, I've built an MSDOS port of Emacs 22.0.91 and found I
couldn't reproduce the original problem in it.  So I guess the issue
of whether the same fix should be applied to the MSDOS port can now be
closed.

As to the concerns expressed by Yamamoto Mitsuharu, I would also
suggest that a redisplay expert looks into them.