public override void FinishedLaunching(NSObject notification)
        {
            mainWindowController = new MainWindowController ();
            var drawingView = new DrawingView(mainWindowController.Window.ContentView.Bounds);

            mainWindowController.Window.ContentView.AddSubview(drawingView);
            mainWindowController.Window.MakeKeyAndOrderFront (this);
            mainWindowController.Window.MakeFirstResponder(drawingView);
        }