Dualhead monitors, xorg, nvidia twinview, and opengl apps.

A common problem when using dualhead monitors in a twinview setup, is that when running full screen opengl apps such as OpenArena, the image will display in the center of your monitors. Instead of it running full screen on one monitor, it will be spanned across your monitors with half of the image on each monitor. To resolve this you need to change your metamode line in /etc/X11/xorg.conf. In Section "Screen", change your Option "metamodes" line to something like this.

Option "metamodes" "1280x1024,1280x1024; NULL,1280x1024"