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

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 03 Nov 2014 18:06:28 -0200
> From: Bruno Félix Rezende Ribeiro <oitofelix@gnu.org>
> CC: rudalics@gmx.at, 18912@debbugs.gnu.org
> 
> The outputs of the 'dump-glyph-matrix' command for both the good and bad
> configurations are in the attached files 'dump-glyph-matrix-good.txt'
> and 'dump-glyph-matrix-bad.txt', respectively; they are identical, though.

So you are saying that this last line:

   33: (1) '  lrwxrwxrwx   1 root root          25 Out 30 22:17 initctl -> /run/systemd/init'

which appears in both the "good" and the "bad" dumps, is nevertheless
displayed (overwrites the mode line) only in the "bad" configuration,
and is not visible at all in the "good" one, is that right?

> For the sake of precision I used the method suggested by Martin:
> evaluating the expression
> 
> (while (y-or-n-p "decrease?")
>   (set-frame-height nil (1- (frame-text-height)) nil t))
> 
> in the requested condition.  In order to not be fooled by a spurious
> mode-line redrawing, I killed the buffer and invoked 'C-x d /dev RET'
> again and the glitch was gone, after one iteration (minus 1 pixel).

So hereby you have your workaround already, for free: just make the
frame one pixel lower.