Thanks So what is the relationship between World and Display then?
Display is the bitmap (Form) which represents the display. Modifying the Display does change what appears on the screen.
The World is a PasteUpMorph that contains cursors and all of the objects beneath it. The World does contain a Canvas, which is responsible for drawing the morphs onto the Display. But the World is a higher-level abstraction.
Mark
-------------------------- Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280 (404) 894-5618 : Fax (404) 894-0673 : guzdial@cc.gatech.edu http://www.cc.gatech.edu/gvu/people/Faculty/Mark.Guzdial.html