Hello,
I almost did everything right I think, following the directions at http://code.google.com/p/pharo/wiki/HowToContribute.
If I did, I believe SLICE-remove-ScreenController-RobRothwell.2 should effectively remove ScreenController from the system.
Please check it out when you get the time; it required small changes changes to Morphic, Graphics, ST80, and System.
I forgot to set the status to "Fixed," however, and can't figure out how to do that!
Take care,
Rob