flutter-quill/doc/configurations/using_custom_app_widget.md

🛠️ Using Custom App Widget

The project uses some adaptive widgets like AdaptiveTextSelectionToolbar which require the following delegates:

1. Default Material Localizations delegate
2. Default Cupertino Localizations delegate
3. Default Widgets Localizations delegate

You don't need to include these since they are defined by default. However, if you are using a custom app or overriding the localizationsDelegates in the App widget, ensure it includes the following:

localizationsDelegates: const [
    DefaultCupertinoLocalizations.delegate,
    DefaultMaterialLocalizations.delegate,
    DefaultWidgetsLocalizations.delegate,
],

You might need more depending on your use case. For example, if you are using custom localizations for your app with a custom app widget like FluentApp from FluentUI, you will also need:

localizationsDelegates: const [
    // Required localizations delegates ...
    FluentLocalizations.delegate,
    AppLocalizations.delegate,
],

📌 Note: In recent versions of FluentApp, you no longer need to add the localizationsDelegates. This is just an example. For more information, refer to the #946.

📄 For additional notes, see the Localizations page.