private NNodeList shapes;

private void CreateDiagram()

{

shapes = new List<NShape>();

      NBasicShapesFactory f = new NBasicShapesFactory(document);

      f.DefaultSize = new NSizeF(100, 100);

      NShape square = f.CreateShape(BasicShapes.Rectangle);

      square.Location = new NPointF(0, 0);

      document.ActiveLayer.AddChild(square);

      NShape circle = f.CreateShape(BasicShapes.Circle);

      circle.Location = new NPointF(0, 200);

      document.ActiveLayer.AddChild(circle);

      document.EventSinkService.NodeBoundsChanged += new NodeEventHandler(EventSinkService_NodeBoundsChanged);

      document.SizeToContent();

      shapes = document.Descendants(NFilters.Shape2D, -1);

}

private void EventSinkService_NodeBoundsChanged(NNodeEventArgs args)

{

      if (args.Node is NShape)

      {

            NShape draggedShape = (NShape)args.Node;

            if (draggedShape.ShapeType == ShapeType.Shape1D)

                  return;

            NRectangleF bounds = draggedShape.Bounds;

            bounds = view.SceneToDevice.TransformBounds(bounds);

            NHitTestContext hitTestContext = view.ProvideDocumentHitTestContext();

            for (int i = 0; i < shapes.Count; i++)

            {

                  NShape shape = (NShape)shapes[i];

                  if (shape == draggedShape)

                        continue;

                  if (shape.HitTest(bounds, hitTestContext))

                  {

                        NStyle.SetFillStyle(shape, new NColorFillStyle(KnownArgbColorValue.Red));

                  }

                  else

                  {

                        shape.Style.FillStyle = null;

                  }

            }

      }

}