public override void AwakeFromNib() { base.AwakeFromNib(); // Get native view for the panel // passing true so that we can embed, otherwise we just get a reference to the control var nativeView = new MyEtoPanel().ToNative(true); nativeView.AutoresizingMask = NSViewResizingMask.MinYMargin; // anchor to top left // position control, keeping auto size of control var contentFrame = Window.ContentView.Frame; nativeView.SetFrameOrigin(new PointF(100, contentFrame.Height - nativeView.Frame.Height - 100)); Window.ContentView.AddSubview(nativeView); }