public static void OpenWindow()
    {
        if (wnd != null)
        {
            return;
        }

        wnd         = GetWindow <OnlineMapsWelcome>(true, "Welcome to Online Maps", true);
        wnd.maxSize = wnd.minSize = new Vector2(500, 440);
    }
 private void OnDestroy()
 {
     wnd = null;
     EditorPrefs.SetBool(PREFSHOWATSTARTUP, false);
 }
 private void OnEnable()
 {
     wnd = this;
 }