I changed desktop settings back to the original 2x2 and problem then does not seem to occur.
Side note: 2x2 desktop however is very unhandy for me (and in general I think) because it is much more difficult to keep in mind how to switch to previous or next desktop using keyboard shortcuts. With 3x1 (or 4x1) I only need to go left for previous desktops or right for next desktops. This is more fluently to remember. In Gnome 2 at least you could see on what desktop you are, now on unity you don't see that any more. See http://brainstorm.ubuntu.com/idea/29858/
I changed desktop settings back to the original 2x2 and problem then does not seem to occur.
Side note: 2x2 desktop however is very unhandy for me (and in general I think) because it is much more difficult to keep in mind how to switch to previous or next desktop using keyboard shortcuts. With 3x1 (or 4x1) I only need to go left for previous desktops or right for next desktops. This is more fluently to remember. In Gnome 2 at least you could see on what desktop you are, now on unity you don't see that any more. See http:// brainstorm. ubuntu. com/idea/ 29858/