cSuperClass.cls is yet another compiled in subclasser but with some major differences… this one doesn’t use a module, instead it dynamically generates a machine code window procedure that can operate in one of two modes. a) Filtered mode will only callback on the messages that you specify, each of which can be individually set to call before or after default processing. b) All message mode calls back for all messages after default processing. One significant characteristic of this technique is that it seems to provide immunity to the IDE End button issue that troubles conventional compiled in subclassers. Through these measures, cSuperClass is fast and flexible and safe. Sample project included.