Well, polymorphism can't do everything. In some cases you'll want completly different behaviours depending on the derived type. For instance, in FUI or BlitzUI (i think), you would pass the handle of the gadget and a message to a function and it would do something based on the type of gadget (found in a similar way as mark's method), and do something completly different in diffferent cases. Although, polymorphism would have certaintly helped, as he could have generalized functions such as move, hide, and show.