private void OnControlRemoved(object sender, ContainerControlEventArgs eventArgs)
 {
     RemoveControlEvents(eventArgs.Control);
     if (FocusManager != null)
         FocusManager.ControlTreeChanged();
 }
 private void OnControlAdded(object sender, ContainerControlEventArgs eventArgs)
 {
     WireControlEvents(eventArgs.Control);
     eventArgs.Control.RedrawRequested += (o, args) => RedrawRequested(o as Control, args);
     if (FocusManager != null)
         FocusManager.ControlTreeChanged();
 }