This service is responsible for providing the MenuItems to show in a menu frontend and indicating which (if any) MenuItem is currently selected.
The list of MenuItems to display in a menu frontend.
The MenuItem.Id of the currently selected MenuItem or null if no MenuItem is selected.
Whether captions should be shown next to menu items when presented by a menu frontend.
Should be called when the frontend focus in the system UI has changed. id is the menu item that users use to access the focused frontend. id can be null to indicate that the focused frontend does not have a menu item.
May be called upon clicking a MenuItem in a menu frontend.
Debug API, Toggle the visibility of the labels