public void SelectNext()
{
if (_items.LastOrDefault() == _selected) return;
_selected.Reset();
_selected = _items[_items.FindIndex(x => x == _selected) + 1];
}
public void SelectPrev()
{
if (_items.FirstOrDefault() == _selected) return;
_selected.Reset();
_selected = _items[_items.FindIndex(x => x == _selected) - 1];
}
public void AddItem(SubMenu item)
{
_items.Add(item);
if (_items.Count == 1)
_selected = _items[0];
}