Comment 21 for bug 206998

Today I started again to work with the problem (not having compiz with a correct 1280x800, screen splitted).
I found a solution for my configuration, a docked dell d810 with external 1280x1024 LCD).

First I did a dpkg-reconfigure xserver-xorg, to start with fresh new xorg.conf, because I had a previous old installation. The new xorg.conf is very simple, like showed here
http://www.thinkwiki.org/wiki/Xorg_RandR_1.2

Then, I had only to add a few line in xorg.conf section Screen to manage the docked monitor, which has to manage a 1280x1024 resolution:
       SubSection "Display"
           Depth 24
           Modes "1600x1200" "1280x1024" "1280x800" "1024x768" "800x600" "640x480"
           # ADD A VIRTUAL LINE TO PROVIDE FOR THE LARGEST SCREENS YOU WILL HOTPLUG
           Virtual 2048 2048
       EndSubSection

And so the laptop works well, with or without docked LCD external monitor.
The trick is to use a clean xorg.conf, with correct configuration for the new xorg-server included in Hardy.