1. A computer implemented method of displaying on a computer system display, compound objects composed of plural object types wherein said computer system does not have a corresponding part handler for one or more said object types, comprising steps in said computer of: attempting to display each said object and, for any said object which cannot be displayed due to the lack of a proper part handler corresponding to the type required for said object; determining if the hierarchical class of said object type which could not be displayed has an existing superclass in said computer system, and if a superclass of said object's hierarchical class is found to exist, employing the part handler of said superclass to display said object; but if a superclass of said class of said object type which could not be displayed does not exist in said computer sysem, repeating said determining step to determine whether a superclass does exist for said superclass which was not found to exist and, if such a class does exist, repeating said employing step using the part handler of said superclass' superclass; and repeating said steps until either a usable part handler is found for a superclass or said class structure is exhausted.