I'm using Ubuntu 11.10. Sometimes I get strange artifacts on the screen, mainly in the Unity toolbar, but also in some applications such as Firefox. I can't find a way to reproduce the problem, it seems to appear randomly.
I can continue working because the system is still usable, but it's a bit dissapointing.
I took a screenshot to clarify what's happening.
Can you help me with this? Thank you very much and sorry for my bad english.
PS: I'm using an ATI Radeon x1550 with the default drivers and Unity 3d