johnson@uiucdcsp.cs.uiuc.edu (02/25/88)
Apple Smalltalk is derived from an early version of Smalltalk that did not have pluggable views. Thus, Apple did not delete any classes, they just didn't add them. Since Apple plans to replace the whole MVC system with something else, the problem of incompatibility does not worry them. If you avoid pluggable views, everything else seems reasonably compatible. Also, it is possible to port pluggable views, though this probably violates Xerox's copywrite.