Source article
Basically, there is a line in /etc/X11/xorg.conf that contains the virtual space setting that needs to be set to your actual resolution... I had this problem, but it fixed itself when I installed 173.14.12 via EnvyNG...
Hmmm... but now as I check my old xorg.conf's I don't see a virtual setting in any of them... well, maybe this will help someone out there.
Or if you have teh problem, upgrade your nvidia driver like I did and maybe that will help you as well.
Basically, there is a line in /etc/X11/xorg.conf that contains the virtual space setting that needs to be set to your actual resolution... I had this problem, but it fixed itself when I installed 173.14.12 via EnvyNG...
Hmmm... but now as I check my old xorg.conf's I don't see a virtual setting in any of them... well, maybe this will help someone out there.

Or if you have teh problem, upgrade your nvidia driver like I did and maybe that will help you as well.