Binary package hint: gnome-control-center
gnome-display-properties seems to be unable to set vitual size in xorg.conf appropriately in this case:
I am using a laptop with an Intel GM965 card and an LCD of 1280x800
1) Log into gnome
2) plug a 1920x1200 external VGA LCD
3) Start gnome-display-manager
First issue: the maximum display resolution of the external display is 1280x1024. (This is the same reported by xrandr and I think it is caused by the fact that the Vitual resolution at that time is 1280x1024).
4) Enable the external display at the maximum allowed resolution and put it on the side of the laptop LCD.
5) g-d-m says it needs to change xorg.conf
6) g-d-m changes the the virtual size to 2560 (i.e. 1280+1280).
Expected result: there should be a way to change it to the real sum of resolution: 1280+1920 =3200.
ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 9.04
Package: gnome-control-center 1:2.26.0-0ubuntu1
ProcEnviron:
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: gnome-control-center
Uname: Linux 2.6.28-11-generic x86_64
The only way to get the correct virtual size without manual editing of xorg.conf seems to be starting X with the external LCD already connected. In this way the visrtual size goes up to the resolution of the external display.