I'm not sure if I should post this in the MBP or iMac forum, so forgive me if I'm in the wrong place. I purchased a 15" MacBook Pro with Thunderbolt about a month ago and have been using my late 2009 iMac as a second display with no problems. Today I took the MBP with me to work away from the office and when I returned and plugged the iMac back in, the MBP display went a bit dark and the iMac went to full brightness. I have to increase the MBP brightness to make it look correct and I have no way of adjusting the iMac brightness. The brightness on both machines works perfectly fine when they are not connected. Could there be a problem with the video card in my new MacBook Pro?