I had GeForce and Ubuntu 12.04 and everything was ok. Then I had to switch to Radeon 9550. Installed packages like it was written somewhere in docs. Had to create xorg.conf manually to have 1280x720, it was only like 800x600.
Now I have 2 screens in Ubuntu settings and 2 top menus (that with date, username etc) at the same time.
How to remove extra screen?