I resolved following this link: http://www.ubuntuforums.org/showthread.php?t=20976 and adding
DisplaySize 338 203 # 1280x1024 96dpi
in the first "Monitor" section of xorg.conf
I resolved following this link: http:// www.ubuntuforum s.org/showthrea d.php?t= 20976
and adding
DisplaySize 338 203 # 1280x1024 96dpi
in the first "Monitor" section of xorg.conf