It falls within the nokia warrenty and can be demanded for a repair.

The person i spoke from the nokia care center told me it mostly has to do with water damage. The n96 also had this problem allot he said.

Something i didn't know is that every nokia has a water indicator on it. wich makes it possible for nokia to see wether or not a phone has had water damage in the past. the guy there told me that.

If i were you, and your n900 has not had water damage, i would bring the n900 in for repair. It didnt bother me in the first place but it looked like it became worse, and i started to anoy the fact that my 600 dollar device didn't have a descent screen.