public Point?GetNormalizedPosition() { if (ParentGraph != null) { if (ParentGraph.MainCanvas != null) { Point p = ParentGraph.NormalizePointToScreen(new Point(DataIndex, DataCollection[DataIndex])); p.X = p.X - thumb.Width / 2; p.Y = p.Y - thumb.Height / 2; return(p); } } return(null); }