Autocomplete not working on Mma9 on Linux

I started using Mathematica 9 on Ubuntu 12.10 and, sometimes, autocomplete doesn't work. The suggestions window shows up for just a fraction of second, and quickly disappears.

Do you have any idea on how I can sold this problem?

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It works for me on Fedora 18; can you make the "sometimes" more precise ? Is it random ? –  b.gatessucks Apr 24 at 10:17
Yep, it really is random (though most of the times it just disappears very quickly). It is very rare for me to be able to use the autocomplete, and after working with it on Windows, it becomes really annoying not being able to use it. –  Sosi Apr 24 at 10:20
@Sosi Can you check that "ReleaseID" /. SystemInformation["FrontEnd"] gives "9.0.1.0 (4092720, 4092443)"? If not, re-download Mathematica from the user portal and re-install it (or bug your sysadmin ...) –  Szabolcs Apr 24 at 15:27
It gives ""9.0.1.0 (4055667, 4055631)". Seems like I need to redownload it again.. Thanks! –  Sosi Apr 24 at 15:49