title: Working with 2 UINavigationControllers inside a ViewController as Child causes only 1 to respond, the other does not respond
body: <p>I'm working with a project where I start with a ContainerViewController having 2 controllers added as a child:</p>
  <pre><code>func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
  
      guard let scene = (scene as? UIWindowScene) else { return }
      window = UIWindow(windowScene: scene)
      window?.rootViewController = ContainerViewController()
      window?.makeKeyAndVisible()
  }
  </code></pre>
  <p>The ContainerViewController:</p>
  <pre><code>class ContainerViewController: UIViewController {
  
  
  var panGestureRecognizer: UIPanGestureRecognizer!
  
  
  private var menuWidth: CGFloat = UIScreen.main.bounds.width - 50
  
  let menuController = SideMenuViewController()
  let mainController = MainViewController()
  
  override func viewDidLoad() {
      super.viewDidLoad()
      addChildVCs()
      
      panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
          view.addGestureRecognizer(panGestureRecognizer)
  }
  
  private func addChildVCs() {
      
      addChild(menuController)
      menuController.view.frame = CGRect(x: 0 - view.frame.size.width, y: 0, width: menuWidth, height: view.frame.size.height)
      view.addSubview(menuController.view)
      menuController.delegate = self
      menuController.didMove(toParent: self)
      
      addChild(mainController)
      mainController.delegate = self
      view.addSubview(mainController.view)
      mainController.didMove(toParent: self)
  }
  </code></pre>
  <p>With this panGesture I just show/hide a SideMenu, nothing strange here.</p>
  <p>Inside this MainViewController, I have a TabBarController named mainController and another UINavigationController that store user conversations, named ConversationViewController(), both added as a child like this:</p>
  <pre><code>class MainViewController: UIViewController {
  
  let mainController = MainTabController()
  let conversationNavigationController = UINavigationController(rootViewController: ConversationViewController())
  
  override func viewDidLoad() {
      super.viewDidLoad()
      addChildVCs()
  }
  
  private func addChildVCs() {
      addChild(mainController)
      mainController.menuDelegate = self
      view.addSubview(mainController.view)
      mainController.didMove(toParent: self)
      
      addChild(conversationNavigationController)
      conversationNavigationController.view.frame = CGRect(x: view.frame.size.width, y: 0, width: view.frame.size.width, height: view.frame.size.height)
      view.addSubview(conversationNavigationController.view)
      conversationNavigationController.didMove(toParent: self)
      
  }
  </code></pre>
  <p>The conversationNavigationController origin.x point is starting at the end of the mainController (tabBar) so I can panGesture to the right and show/hide this other UINavigationController.</p>
  <p>The problem is when I start the execution I can interact with the mainController(tabBarController) but when I swipe to the right and I have the conversationNavigationController on screen, it doesn't respond to any actions.</p>
  <p>Basically I'm working with 2 navigationControllers at the same time but I don't understand why 1 is working and the other one does not respond to any actions.</p>
  <p>Any clue on what's the problem? I can provide more code if needed!</p>
  <p>Thanks in advance</p>