private void StartPortOnSizeChanged(object sender, SizeChangedEventArgs sizeChangedEventArgs) { var startPort = sender as Port; if (startPort != null) { startPort.Origin.X = startPort.TranslatePoint(new Point(startPort.Width/2, startPort.Height/2), VplControl).X; startPort.Origin.Y = startPort.TranslatePoint(new Point(startPort.Width/2, startPort.Height/2), VplControl).Y; } }