Subject: bug#18912: 24.4; mode-line corruption on graphical frames in dual-headed display

From: Eli Zaretskii <[email-masked]>
Date: Mon, 03 Nov 2014 18:23:15 +0200

> From: Andreas Schwab <[email-masked]>
> Cc: Bruno Félix Rezende Ribeiro <[email-masked]>,
>   [email-masked]
> Date: Mon, 03 Nov 2014 10:08:02 +0100
> 
> Eli Zaretskii <[email-masked]> writes:
> 
> > Emacs never writes buffer contents where the mode line should be, so
> 
> Unless it needs to write a partial line just above the mode line.
> 
> > this problem could only happen if Emacs for some reason becomes
> > confused about the window dimensions.
> 
> Or the clipping rectangle is wrong for any reason.

It could be that, yes.  Although I generally need to enlarge the frame
by at least 3 pixels before Emacs enables another glyph row for such
clipped display.

Anyway, I hope dump-glyph-matrix will show if this is the case.