johnson@uiucdcsp.CS.UIUC.EDU (04/18/86)
Here is some more information. When you create a new class, you actually use the subclass:instanceVariableNames:classVariableNames:poolDictionaries:catagories: message. To create a class with multiple superclasses, you should use the subclass:otherSupers:instanceVariableNames:classVariableNames:catagories: message. Both messages are defined in class Class. Note that the contents of the class definition window is actually a piece of Smalltalk code. When you accept it, the code is compiled and executed, resulting in sending one of the above messages to the superclass. There is a message somewhere that defines the template for defining a new class. If you change that message then you can get a template that has a slot for multiple superclasses. If not, you can just edit the template until it has the proper form.