The EventMask determines which event types will be sent
from the controller to the Notify object. By setting bits in the
EventMask, specific events can be sent to the Notify object when
they occur or by clearing specific bits, the events can be ignored.
By default, no Events will occur until the EventMask is set.
The Event, EventMgr, and Notify objects are used with the EventMask
to handle controller events.