I recently updated to 13.04. About half the times when I open Unity dash (super / windows key) and start typing the input field loses focus after a couple of keystrokes. I'll then have to set the focus again by using the mouse - needless to say that this is very annoying.
It happens in 90% of the cases, but it is not always reproducible by typing the same text again. My best guess is that it occurs when some Unity lenses return their individual search results (that might be cashed the next time) and probably steal focus.
I disabled all online lenses which did not change the behaviour.
Anyone with similar issues / ideas / solutions?
UPDATE: posted this question about a month ago with very limited feedback. My guess is that most people don't have this issue.
Try to switch KDE Compatibility' in CCSM it seemed to solve the problem for me.
Although as you say its hard to reproduce, but usually it occurred after restart and since then its ok.