I have a 13" MBP 2.53GHz, and I absolutely love it. However, I have one issue. I am using an Apple display port to DVI adapter to run the MBP in clamshell mode with my Samsung 221BW monitor. On websites or programs with a dark grey background, the screen flickers. The resolution is set to 1680x1050 (native) and 60Hz. Does anybody else have this problem? Any ideas as to fixing it?