Display shifted when switching between computers

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http://askubuntu.com – I have a kvm-switch (keyboard, video, mouse) to switch between my 2 computers. One runs on Ubuntu(latest version), the other on windows 7. When i switch from one computer to the other, my display is not correct. It is out of line(everything is shifted to far to the left/right). When I press the autoset-button on my screen, it works fine. I didn't have this problem back when both computers ran windows. The problem is that every time i switch between my computers, i have to press the autoset button on my screen to get a correct display. (HowTos)