public bool LoadTPadApp(ITPadApp tPadApp, bool foreground = true)
        {
            if (tPadApp == null)
            return false;

              (tPadApp as UserControl).VerticalAlignment = System.Windows.VerticalAlignment.Stretch;
              (tPadApp as UserControl).HorizontalAlignment = System.Windows.HorizontalAlignment.Stretch;
              if (!gTPadApp.Children.Contains(tPadApp as UserControl))
              {
            gTPadApp.Children.Add(tPadApp as UserControl);
            tPadApp.Closed += tPadApp_Closed;
              }

              if (foreground)
            Show(tPadApp);
              else
            Hide(tPadApp);

              return true;
        }
 public void Show(ITPadApp tPadApp)
 {
     UserControl app = tPadApp as UserControl;
       int nextIndex = gTPadApp.Children.Cast<FrameworkElement>().Max(element => Canvas.GetZIndex(element)) + 1;
       Canvas.SetZIndex(app, nextIndex);
       app.Visibility = System.Windows.Visibility.Visible;
 }
 public void Hide(ITPadApp tPadApp)
 {
     UserControl app = tPadApp as UserControl;
       app.Visibility = System.Windows.Visibility.Collapsed;
 }