public ApplicationPanel(ApplicationPanelHelper <FrameworkElement, Size, Rect> helper)
 {
     _helper = helper;
 }
        IApplicationPanel <FrameworkElement, Size, Rect> ISuperPanel <FrameworkElement, Size, Rect> .CreateChild(ApplicationPanelHelper <FrameworkElement, Size, Rect> helper)
        {
            var panel = new ApplicationPanel(helper);

            Children.Add(panel);
            return(panel);
        }