public void Update(MouseState current, Input previous)
        {
            int marked = -1;

            for (int i = 0; i < _panel.Count; i++)
            {
                OptionsButton     btn   = _panel[i];
                OptionButtonState state = btn.MarkedState;
                btn.Update(current, previous);
                if (btn.MarkedState != state)
                {
                    marked = i;
                }
            }
            if (marked != -1)
            {
                for (int i = 0; i < _panel.Count; i++)
                {
                    if (i != marked)
                    {
                        _panel[i].UnMark();
                    }
                }
            }
        }
 public void Add(OptionsButton button)
 {
     _panel.Add(button);
     _panel[_panel.Count - 1].AllowClickToUnmark = false;
 }