Mode-line draw/refresh problem in a Multi-headed X11 system.

Mode-line draw/refresh problem in a Multi-headed X11 system.

[Bruno Félix Rezende Ribeiro]

Hello.  I set up my netbook's X Window System to work in a multi-headed
fashion with 2 monitors, one LVDS (LCD Laptop Panel - 1024x600) and one
external VGA (CRT - 1280x1024).  Both physical screens are in one
logical X screen (localhost:0.0) and LVDS display is at right of VGA
display.  My window manager is StumpWM and it assign one Frame to each display.
I run an Emacs server frame in the larger screen and a client frame in
the other.

However there is a problem with the mode-line in both Emacs frames.
When the last text line in a window should be partially covered by
mode-line, the text line is drawn over mode-line.  This don't happens if
mode-line covers completely last window line.

The following Emacs-lisp expressions _don't_ force Emacs to redraw the
mode-line in a way that fix the garbage:

(redraw-display)
(redraw-frame (selected-frame))
(redraw-modeline)

Nevertheless, "xrefresh" command and StumpWM's "redisplay" command does
the job.

One interesting thing is that if I start X11 with the VGA external
screen _disconnected_, everything is fine.  I wonder if it is a Emacs
problem or a StumpWM problem in inform to Emacs the total application
dimensions or something like that.

Anyone has experienced this?  Any idea about problem's origin or a fix
solution?

Helpful information:

In GNU Emacs 23.4.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2012-02-08 on felix-laptop
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
configured using `configure  '--with-x-toolkit=athena' '--with-crt-dir=/usr/lib/i386-linux-gnu' 'CFLAGS=-O3''
-- 
 ,= ,-_-. =.  Bruno Félix Rezende Ribeiro (oitofelix)
((_/)o o(\_)) Uns o chamam de super-vaca...
 `-'(. .)`-'  Outros de hyper-touro...
     \_/      Eu o chamo simplesmente: meta-gnu!