I am trying to create an app using PencilKit. I have the following code in one of my ViewControllers.```override func viewDidAppear(_ animated: Bool) { super.viewDidAppear(animated) guard let window = view.window, let toolPicker = PKToolPicker.shared(for: window) else { return } toolPicker.setVisible(true, forFirstResponder: canvasView) toolPicker.addObserver(canvasView) canvasView.becomeFirstResponder()}```Although I am calling the setVisible function and making the canvasView the firstResponder, my toolPicker is not showing up, and printing toolPicker.isVisible is false.