fix: Properly handle app layout suspended state (#3720)

Author: just-boris

src/app-layout/visual-refresh-toolbar/multi-layout.ts

@@ -98,7 +98,10 @@ export function mergeProps(
   return Object.keys(toolbar).filter(key => key !== 'ariaLabels').length > 0 ? toolbar : null;
 }
 
-export function useMultiAppLayout(props: SharedProps, isEnabled: boolean) {
+export function useMultiAppLayout(
+  props: SharedProps,
+  isEnabled: boolean
+): { registered: boolean; toolbarProps: ToolbarProps | null } {
   const [registration, setRegistration] = useState<RegistrationState<SharedProps> | null>(null);
   const { forceDeduplicationType } = props;
   const isToolbar = useAppLayoutFlagEnabled();
@@ -111,9 +114,13 @@ export function useMultiAppLayout(props: SharedProps, isEnabled: boolean) {
       setRegistration({ type: 'primary', discoveredProps: [] });
       return;
     }
-    return awsuiPluginsInternal.appLayoutWidget.register(forceDeduplicationType, props =>
+    const unregister = awsuiPluginsInternal.appLayoutWidget.register(forceDeduplicationType, props =>
       setRegistration(props as RegistrationState<SharedProps>)
     );
+    return () => {
+      unregister();
+      setRegistration({ type: 'suspended' });
+    };
   }, [forceDeduplicationType, isEnabled, isToolbar]);
 
   useLayoutEffect(() => {
@@ -124,7 +131,7 @@ export function useMultiAppLayout(props: SharedProps, isEnabled: boolean) {
 
   if (!isToolbar) {
     return {
-      registered: 'primary',
+      registered: true,
       // mergeProps is needed here because the toolbar's behavior depends on reconciliation logic
       // in this function. For example, navigation trigger visibility
       toolbarProps: mergeProps(props, []),

src/internal/plugins/controllers/app-layout-widget.ts

@@ -12,7 +12,14 @@ interface SecondaryRegistration<Props> {
   update: (props: Props) => void;
 }
 
-export type RegistrationState<Props> = PrimaryRegistration<Props> | SecondaryRegistration<Props>;
+interface SuspendedRegistration {
+  type: 'suspended';
+}
+
+export type RegistrationState<Props> =
+  | PrimaryRegistration<Props>
+  | SecondaryRegistration<Props>
+  | SuspendedRegistration;
 type RegistrationType = RegistrationState<unknown>['type'];
 
 type RegistrationChangeHandler<Props> = (