private void Start()
{
WDOCtrl = Singleton.Instance <WindowManager>();
WDOCtrl.AddGroup(GroupType, this);
windows = WDOCtrl.Windows;
if (Group != null && !Group.Contains(WindowType.None))
{
Group.Add(WindowType.None);
}
BackButton.OnClickEvents += delegate { Back(); };
preWindow = new Stack <WindowType>();
}