public void Stop()
 {
     ActivationTracker.Activated   -= HandleActivated;
     ActivationTracker.Deactivated -= HandleDeactivated;
     ActivationTracker.Stop();
 }
 public void Start()
 {
     ActivationTracker.Activated   += HandleActivated;
     ActivationTracker.Deactivated += HandleDeactivated;
     ActivationTracker.Start();
 }