code: func (menu *Menu) setDisplayed(displayed bool) {
  	menu.Displayed = displayed
  
  	for _, child := range menu.Items {
  		if child.IsSubMenu() {
  			child.SubMenu.setDisplayed(displayed)
  		}
  	}
  }
docs: /*
  setDisplayed sets the menu Displayed attribute, this is a tracking attribute and has no effect on ThrustCore or UI Layer. Thus is is private.
  */