private void MetroWindow_Closing(object sender, System.ComponentModel.CancelEventArgs e)
 {
     if (groupColorHelper != null)
     {
         groupColorHelper.SaveSettings();
         if (SettingChanged != null)
         {
             SettingChanged.BeginInvoke(this, new SettingChangedEventArgs(groupColorHelper.Name, SettingChangedType.UserGroupColor, groupColorHelper), null, null);
         }
     }
 }