Comment 2 for bug 336721

This is beginning to look like a deeper problem with the current Xorg. I am becoming convinced the symptoms are caused by the same issue that invokes bug #331918 "Clipped area for multiple X screens with different dimensions".

This issue affects Metacity and Compiz which suggests there is a common cause.

With one video display adapter and two X screens I've found it impossible to start many applications on :0.1 regardless of how I try. Here's a really good example - all these cause the window to open on :0.0

From gnome-terminal instance running on :0.1 (same result if it is running on :0.0)

env | grep DISPLAY
DISPLAY=:0.1

DISPLAY=:0.1 nautilus
nautilus --display=:0.1
nautilus --screen=1

Any application in the standard Gnome menu will start on :0.0. Custom additions to the gnome panel can be started on the correct screen. E.g:

evolution --display=:0.1 --component=mail
firefox %u

Notice here that Firefox is one of the few applications that correctly detects the current screen.

Combining these experiences with the issues discovered for compiz (where it seems as if compiz gets the wrong or misleading screen information from the X-server) I'm beginning to think that the X-server information functions are giving out screen 0 data.