title: Subview passes touches to subview beneath it
body: <p>I have added a subview like so:</p>
  
  <pre><code>func showPlayerView2() {
      self.view.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height - 56)
      //let theView = myView
      let theView = PlayerView()
      theView.willMove(toParentViewController: self.navigationController)
      self.navigationController?.addChildViewController(theView)
      theView.view.isUserInteractionEnabled = true
      theView.playPauseButton.isUserInteractionEnabled = true
      self.navigationController?.view.bringSubview(toFront: theView.view)
      self.navigationController?.view.addSubview(theView.view)
      theView.view.frame = CGRect(x: 0, y: self.view.frame.maxY, width: 375, height: 56)
  
      theView.didMove(toParentViewController: self.navigationController)
      self.view.layoutSubviews()
  }
  </code></pre>
  
  <p><code>PlayerView</code> Has a button that is supposed to print something to the screen when pressed.</p>
  
  <p>Even after setting <code>isUserInteractionEnabled</code> to <code>true</code>, it still does not register touches and they pass through to the view below it. I have looked at nearly every SO question relating to this and none of the answers have worked. What can I do to fix this?</p>