Apple - Weird display issue on OS X Lion when switching external monitor

I am also experiencing the same problems and have posted a thread to the Macbook Pro Apple Forums. While there isn't any answer yet you might be interested in following along that thread.

So far the only reliable way to fix it would be to restart the machine. Or to log out and log back in. Neither method is satisfactory.

I've had an identical problem on my 2010 MBP since upgrading to Lion last fall. Here's what I did today that seemed to fix the problem:

1) Go into Macintosh HD and find /Library/colorsync/profiles/displays
2) Move all files in the 'displays' directory into a backup folder on your Desktop
3) Open System Preferences > Displays and click on "Color" for each of your displays
4) Your computer will take a few seconds and create a fresh display file for each monitor.

After doing this all the weird screen artifacts and colors have gone away on both my MBP LCD display and my 19" external monitor connected with mini-DVI.

I have been able to work around the issue using the free app gfxCardStatus to switch between integrated and discrete graphics on my MBP.

It doesn't matter which you use, switching to the other one fixes the problem until next time.