/// <summary>
        /// Delegate function used to turn custom grips on
        /// </summary>
        public void TurnOnGrips(RhinoObject rhObject)
        {
            if (rhObject == null)
            {
                return;
            }

            var polyline_curve = rhObject.Geometry as PolylineCurve;

            if (polyline_curve == null)
            {
                return;
            }

            if (!SampleCsRectangleHelper.IsRectangle(polyline_curve))
            {
                return;
            }

            var rectangle_grips = new SampleCsRectangleGrips();

            if (!rectangle_grips.CreateGrips(polyline_curve))
            {
                return;
            }

            rhObject.EnableCustomGrips(rectangle_grips);
        }