I've got a docked Thinkpad R51 running Fed12 with a 20" 1600x900 external monitor plugged in. Both KDE and Gnome recognized the new external screen and wanted to do dual screen just fine. The problem is, only Gnome allowed me to disable the laptop screen, which is what I want. As I'm saying, the laptop is docked, lid down -- don't want to see or know about its screen. But then in Gnome a ./compiz-check test says I'm running 2624x900. No doubt it still thinks the laptop screen is in business. And when I try KDE, sure enough, it acts like I'm running both screens. That is, my mouse wanders far to the right into an imaginary laptop screen space where, incidently, the panel and apps are; my 20" external is happy, but totally ignored. Ironically, can grab things on the virtual laptop screen and drag them over to work on, or I can open up the laptop and see the supposedly disabled screen running. I have even dragged display settings box over and supposedly, again, disabled the laptop screen -- but no dice. KDE just won't let the laptop screen be disabled. How can I truly disable the laptop screen and have just the external monitor?