An object-oriented item is used to define the behavior of an item in a dialog box in a windows environment. A class hierarchical library is established with a base class setting up initial definitions of instance variables and methods used to define the behavior of a customized item. An applications developer can create customized items for a dialog box by creating subclasses. The subclasses will inherit portions of the superclasses, and the developer will customize the items by overriding certain methods. The object, an instance of the class, is referenced by a resource associated with an application.