internal void UnregisterPresenter(SwitchPresenter presenter, DependencyObject container)
 {
     if (container != null)
     {
         _presenters.Remove(presenter);
         presenter.SwapTheTemplate(null, false);
     }
 }
        internal UIElement RegisterPresenter(SwitchPresenter presenter)
        {
            UIElement      result = null;
            AnimationPanel ignore;

            result = AnimationPanel.FindAncestorChildOfAnimationPanel(presenter, out ignore);
            if (result != null)
            {
                _presenters.Add(presenter);
                presenter.SwapTheTemplate(ActiveSwitchTemplate, false);
            }
            return(result);
        }