public static void Open()
 {
     if (r_Current != null)
         r_Current.Activate();
     else
     {
         r_Current = new ScreenshotTool() { Owner = Application.Current.MainWindow, DataContext = new ScreenshotToolViewModel() };
         r_Current.Show();
     }
 }
 public static void Open()
 {
     if (r_Current != null)
     {
         r_Current.Activate();
     }
     else
     {
         r_Current = new ScreenshotTool()
         {
             Owner = Application.Current.MainWindow, DataContext = new ScreenshotToolViewModel()
         };
         r_Current.Show();
     }
 }
        protected override void OnClosed(EventArgs e)
        {
            r_Current = null;

            base.OnClosed(e);
        }
        protected override void OnClosed(EventArgs e)
        {
            r_Current = null;

            base.OnClosed(e);
        }