You might want to set properties or call methods that are implemented in the superclass of the source object. The Assistant interrogates the IDL source object to obtain the properties, methods and method parameters. It also uses the OBJ_CLASS method to obtain the superclasses of the source object class, and for each user class also obtains the properties, methods and method parameters. This is a recursive process that requires interrogating each superclass for its superclasses. Built-in IDL superclasses will not be included in the wrapper definition.
The routine used to extract object information, IDL's ROUTINE_INFO function, can obtain the methods of a built-in object class. However, because ROUTINE_INFO does not provide parameter information for built-in routines, the Assistant is unable to extract the properties (parameters to SetProperty or GetProperty) or the parameters of object methods for a built-in superclass. The built-in superclasses are not presented in the project tree view.
To obtain wrapper routines to modify properties of built-in superclasses, you must add an explicit property handler to the SetProperty and/or GetProperty methods for the superclass property. To obtain wrapper routines to call methods of built-in superclasses, you must add an explicit method to their source object that calls the superclass method.