First, I must say that I do not have PPA or any experimental packages enabled.
Just now I installed the GIMP using kpackagekit. When I tried to start it using icon in the application menu, it didn't start.
I tried running it from the terminal, and it said that it crashed with a segmentation fault.
The question is : is there anything that I can do to install (or reinstall it) properly? I am sure they wouldn't release it if it was crashing like that
Google revealed this - as an aside - weirdest solution I've seen - but a known bug
Set your gtk appearance to Raleigh, launch Gimp once, and then change back to whatever theme you were using before.
i.e.