private void OnGridChanged(object sender, RoutedEventArgs args)
        {
            args.Handled = true;
            if (_ignoreControls)
            {
                return;
            }

            Grid = null;
            PolygonGridBox.InvalidateVisual();
        }
 protected override void OnMouseMove(MouseEventArgs args)
 {
     base.OnMouseMove(args);
     args.Handled = true;
     PolygonGridBox.HandleMouseMove(args);
 }
 protected override void OnMouseDown(MouseButtonEventArgs args)
 {
     base.OnMouseDown(args);
     args.Handled = true;
     PolygonGridBox.HandleMouseDown(args);
 }