protected void OnMembersFormatChanged(DiagramEventArgs e)
        {
            var handler = MembersFormatChanged;

                if (handler != null)
                    handler (this, e);
        }
        protected void OnGroupSettingChanged(DiagramEventArgs e)
        {
            var handler = GroupSettingChanged;

                if (handler != null)
                    handler (this, e);
        }