Comment #3 on issue 502 by MathStuf@gmail.com: Multihead trouble docs update -- xrandr required for proper display http://code.google.com/p/xmonad/issues/detail?id=502 "randr" is a contraction of "Resize and Rotate" which allows you to switch up your monitor configuration at runtime (it's outside drivers so that every driver doesn't need something like the nvidia-settings GUI). This link[1] might be of interest to you. The driver is probably seeing one screen after the driver maps the two displays together. Does your nvidia card have two GPUs? There also seems to be indications that the nvidia driver might act weird when Xinerama and Xrandr are enabled. [1]https://wiki.archlinux.org/index.php/NVIDIA#Enable_screen_rotation_through_X...