No. It means something like, "I have done *all* the handling that this
event requires", and it will stop base classes from doing any further
handling of the event. This can be useful when you're trying to
suppress action in the base class (e.g. ignore a keystroke in
KeyDown), but in other cases - e.g. updating a "number of characters
typed" display in KeyDown - you want the control to operate as normal,
with the *addition* of your event handler.