We have in three MacPros two Radeon HD 5770 with the same problem.
The finder on desktop is on work clean (no icons, no drives). All desktop icons are invisible.
We will see the icons then we make a selection all over desktop. After the selction is the icons visible.
Thats the same problem on all 3 MacPros and ithink that ist a general problem vom AMD.
Please help me.