/// <summary>
        /// Called when the columns need to be populated.
        /// </summary>
        /// <param name="listModel"></param>
        /// <param name="e"></param>
        private void Chain_FetchColumns(TListModel listModel, ListContentEventArgs e)
        {
            _BaseFetchColumns(listModel, e);

            var identifier = GetListIdentifierAction(listModel);
            var inSubset   = ModelSubsetList.Contains(identifier);

            e.Checked = inSubset;
        }
        /// <summary>
        /// Called whent the control wants text for the columns for a record.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Control_FetchRecordContent(object sender, ListContentEventArgs e)
        {
            var listModel = e.Record as TListModel;

            if (listModel != null)
            {
                FetchColumns(listModel, e);
            }
        }