An end user can use the following keys to interact with the widget.
|←||Closes the submenu and focuses on its parent item.|
|→||Opens the submenu of the focused item.|
|Home||Sets focus to the first item in the menu/submenu.|
|End||Sets focus to the last item in the menu/submenu.|
|Space||Switches the focused item to the selected state.|
|Enter||Chooses the focused item.|