XtDispatchEventToWidget [XtInsertEventTypeHandler] (3x)  - extension event handling
XtInsertEventTypeHandler (3x)  - extension event handling
XtRegisterExtensionSelector [XtInsertEventTypeHandler] (3x)  - extension event handling
XtRemoveEventTypeHandler [XtInsertEventTypeHandler] (3x)  - extension event handling
XtSetEventDispatcher [XtInsertEventTypeHandler] (3x)  - extension event handling