So I have an additional monitor for my MBP, and it was fine before. Then all of a sudden, without me changing anything, the second display got duller, and no longer can I select 1680xwhatever. It will only let me choose 1440X900. The MBP display is as sharp as it was, and before the second display was exactly the same. But as said it's all screwed up. I need suggestions plz.