EDIT: the setup which it stays at is the last one, Multi-display desktop with display(s) 2.
This is the problem: with an ATI videocard, I set up dual monitor with the driver's own program. However, for some reason, the top ~200px isn't displayed and at the down ~200px there is only a black line, but only for one monitor. Also, somehow, even after applying, the setup does not change anything (even after restart). How can this be solved?
Update: when it is set to both monitors display the same, there is no black line, but when it is set to different, there is. And it still seems that applying does not work fine.