Deleting a Class Definition
Deleting a class definition automatically deletes all instances of that class, and all instances of any subclasses that inherit it. Instance deletion occurs because an instance requires a complete set of information from every superior class within its class hierarchy. When you delete any superior class within that instance's class hierarchy, such information no longer exists, and thus, neither can the instance.
All subclasses of a deleted superior class retain their class definitions. The Notes attribute of any such subclass, however, has an INCOMPLETE status, and states that one or more direct superior classes is not defined. The same notification would appear if the subclass had been created as part of bottom-up development, and the deleted parent class had never existed.
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