showOverlay creates a scene-less UIWindow, so overlays never appear under UIScene lifecycle #8345

Activity

1. sh-bnsl

   added

   platform: iOS

   type: accepted/bug

   on Aug 27, 2026
2. sh-bnsl commented on Aug 27, 2026

   

   sh-bnsl

   on Aug 27, 2026

   Author

   More actions

   Root cause

   RNNCommandsHandler.showOverlay: (current):

   [overlayVC setReactViewReadyCallback:^{
     UIWindow *overlayWindow =
         [[RNNOverlayWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
     overlayWindow.rootViewController = weakOverlayVC;
     [self->_overlayManager showOverlayWindow:overlayWindow];
     // ...
   }];
   [overlayVC render];

   RNNOverlayManager then only does setHidden:NO. That is not enough for a window with no scene.

   Compare with setRoot:, which mutates the already scene-connected _mainWindow:

   [vc setReactViewReadyCallback:^{
     self->_mainWindow.rootViewController = weakVC;
   }];

   Extra detail (New Arch): overlay VCs do not set waitForRender, so reactViewReadyCallback fires immediately and then creates this window. This is not “callback never called”. The callback creates the wrong kind of window.

   ReactNativeNavigation.mainWindow can also create a scene-less window if delegate.window is nil:

   keyWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];

   That is a related footgun for scene-based hosts, but the overlay bug happens even when _mainWindow is already scene-connected.

   Suggested fix

   Create overlay windows with the main window’s scene:

   RNNOverlayWindow *overlayWindow;
   UIWindowScene *windowScene = self->_mainWindow.windowScene;
   if (windowScene) {
     overlayWindow = [[RNNOverlayWindow alloc] initWithWindowScene:windowScene];
     overlayWindow.frame = self->_mainWindow.bounds;
   } else {
     overlayWindow = [[RNNOverlayWindow alloc] initWithFrame:self->_mainWindow.bounds];
   }
   overlayWindow.rootViewController = weakOverlayVC;

   We patched this locally against 8.8.9 and overlays became visible. Using _mainWindow.windowScene is important so the overlay lands on the same scene RNN already owns.

   Please also consider:

   1. Same initWithWindowScene: path for any other extra windows RNN creates.
   2. Avoid initWithFrame: fallback on iOS 13+ when a scene exists — that window will stay invisible.
   3. In mainWindow, if delegate.window is missing, prefer a connected UIWindowScene over initWithFrame:.

   🚀React with 🚀3Reacted by sami4064, Donato Aguirre and MrKinq
3. sh-bnsl

   changed the title [-]`showOverlay` creates a scene-less `UIWindow`, so overlays never appear under UIScene lifecycle (iOS 13+, required on iOS 26/27)[/-] [+]`showOverlay` creates a scene-less `UIWindow`, so overlays never appear under UIScene lifecycle[/+] on Aug 27, 2026
4. MrKinq commented on Sep 16, 2026

   

   MrKinq

   on Sep 16, 2026

   More actions

   Root cause

   RNNCommandsHandler.showOverlay: (current):

   [overlayVC setReactViewReadyCallback:^{
   UIWindow *overlayWindow =
   [[RNNOverlayWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
   overlayWindow.rootViewController = weakOverlayVC;
   [self->_overlayManager showOverlayWindow:overlayWindow];
   // ...
   }];
   [overlayVC render];
   RNNOverlayManager then only does setHidden:NO. That is not enough for a window with no scene.

   Compare with setRoot:, which mutates the already scene-connected _mainWindow:

   [vc setReactViewReadyCallback:^{
   self->_mainWindow.rootViewController = weakVC;
   }];
   Extra detail (New Arch): overlay VCs do not set waitForRender, so reactViewReadyCallback fires immediately and then creates this window. This is not “callback never called”. The callback creates the wrong kind of window.

   ReactNativeNavigation.mainWindow can also create a scene-less window if delegate.window is nil:

   keyWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
   That is a related footgun for scene-based hosts, but the overlay bug happens even when _mainWindow is already scene-connected.

   Suggested fix

   Create overlay windows with the main window’s scene:

   RNNOverlayWindow *overlayWindow;
   UIWindowScene *windowScene = self->_mainWindow.windowScene;
   if (windowScene) {
   overlayWindow = [[RNNOverlayWindow alloc] initWithWindowScene:windowScene];
   overlayWindow.frame = self->_mainWindow.bounds;
   } else {
   overlayWindow = [[RNNOverlayWindow alloc] initWithFrame:self->_mainWindow.bounds];
   }
   overlayWindow.rootViewController = weakOverlayVC;
   We patched this locally against 8.8.9 and overlays became visible. Using _mainWindow.windowScene is important so the overlay lands on the same scene RNN already owns.

   Please also consider:

   1. Same initWithWindowScene: path for any other extra windows RNN creates.
   2. Avoid initWithFrame: fallback on iOS 13+ when a scene exists — that window will stay invisible.
   3. In mainWindow, if delegate.window is missing, prefer a connected UIWindowScene over initWithFrame:.

   I hit the same mainWindow footgun on scene-based apps and fixed it locally in ReactNativeNavigation.mm by preferring an already connected UIWindowScene instead of creating a scene-less UIWindow with initWithFrame:.

   This is the patch I’m currently using:

   - (UIWindow *)mainWindow {
       UIWindow *keyWindow = UIApplication.sharedApplication.delegate.window;
   
       if (keyWindow) {
           return keyWindow;
       }
   
       if (@available(iOS 13.0, *)) {
           for (UIScene *scene in UIApplication.sharedApplication.connectedScenes) {
               if (![scene isKindOfClass:[UIWindowScene class]]) {
                   continue;
               }
   
               UIWindowScene *windowScene = (UIWindowScene *)scene;
   
               if (windowScene.activationState == UISceneActivationStateUnattached) {
                   continue;
               }
   
               keyWindow = [[UIWindow alloc] initWithWindowScene:windowScene];
               keyWindow.frame = windowScene.coordinateSpace.bounds;
   
               UIApplication.sharedApplication.delegate.window = keyWindow;
               return keyWindow;
           }
       }
   
       // Legacy fallback only. With UIScene configured this should not normally be reached on iOS 13+ once the scene has connected.
       keyWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
       UIApplication.sharedApplication.delegate.window = keyWindow;
   
       return keyWindow;
   }
   

   With this change, the RNN main window is attached to a real UIWindowScene when delegate.window is still nil.