I have a MBP connected to a 20" external widescreen monitor. When I am running the computer in lid-closed mode, the MBP is driving the monitor at the highest resolution the monitor supports (1680x1050). But if I am running in a dual screen mode- with the lid open, the external monitor matches the resolution of the MBP screen (1440x990 I think). Is there a way to make the monitor run at the highest resolution while using it as a dual screen? In other words, how can I configure the computer so that the monitor and the MBP screen have independent resolutions? thanks.