code: @Nonnull
    public BootstrapNavbarToggleable addAndReturnToggleable ()
    {
      final String sIDToToggle = GlobalIDFactory.getNewStringID ();
      addToggler (sIDToToggle);
      return addAndReturnToggleable (sIDToToggle);
    }
docs: Shortcut for {@link #addToggler(String)} and
  {@link #addAndReturnToggleable(String)} with an automatically assigned ID.
  
  @return The toggleable to be filled