Comment 9 for bug 39624

First of all, I hate to say the following, I really do.

On my hardware I'm able to reproduce it as well. The problem however is not the Ubuntulooks code, but either cairo or the ati/radeon RENDER extension. However, I don't have anything to back that up with.

The problem probably lies in the gradient code (in either cairo or RENDER), when clipped. A bug report on this subject has been filed at freedesktop: https://bugs.freedesktop.org/show_bug.cgi?id=5518

Now the result as shown on the screenshots in that bug report differs, but I have a feeling that when that's fixed, the button glitches will dissapear too.

I'm not comfortable saying this however, because it feels like I'm trying to make it easy for myself by pushing the problem into other people's hands. Please know that this is NOT my intention. I don't know the inner workings of cairo and RENDER, but seeing as how the Ubunutlooks code works well on vesa, intel and nvidia (afaik), there's not too much I can do except horrible workarounds (like drawing to an off-screen buffer, avoiding any possible kind of acceleration).