I have a Dell 2407FWP monitor w/my machine 2011, and Lion 10.7.2.. From time to time a get a thin vertical line (top to bottom) on the left side of the monitor that remains for a few minutes, than disappears. I tried to re-attach the DVI cable from the monitor or the HDMI adaptor end, but this does not help. Anyone with same ? Is the monitor going bad or its just the connection ? Thank you in advance to anyone with a possible answer.