It would be useful to know what graphics card you're using. Could you attach:
/etc/X11/xorg.conf
/var/log/Xorg.0.log
and the output of running "xrandr --verbose" please?
Also, if you have compizconfig-settings-manager installed, could you check that "Detect outputs" is enabled in System->Preferences->CompizConfig Settings Manager->General Options->Display Settings.
Hm. That does look odd!
It would be useful to know what graphics card you're using. Could you attach:
/etc/X11/xorg.conf
/var/log/Xorg.0.log
and the output of running "xrandr --verbose" please?
Also, if you have compizconfig- settings- manager installed, could you check that "Detect outputs" is enabled in System- >Preferences- >CompizConfig Settings Manager->General Options->Display Settings.