a design / architectural question on airplay.
I have setup an external display in the AppDelegate:

```
UIScreen *externalScreen = UIScreen.screens.lastObject;
self.externalWindow = [[UIWindow alloc] initWithFrame:externalScreenFrame];
self.externalWindow.screen = externalScreen;
self.externalWindow.backgroundColor = [UIColor redColor];

```

Works fine, TV shows an empty screen in red.
Now I have a ViewController with a bunch of subviews, and one view should be shown on the device *and* the external screen. If I try this in ViewController.m:

```
[_appDelegate.externalWindow addSubview:self.deviceAndTVView];

```

deviceAndTVView will only show on the external screen, not on the device anymore. 
What I would need is to have deviceAndTVView on the device, updating itself on touches / user interaction, and mirror those updates on the external screen.

Which is the right path to accomplish that?

Thanks for reading! 
m