o allows grouping.  When a column is clicked
      ' for sorting, we only want to remove any grouped rows:
      .ClearNongrouped
      
      ' See if this column is already in the sort object:
      iSortIndex = .IndexOf(lCol)
      If (iSortIndex = 0) Then
         ' If not, we add it:
         iSortIndex = .Count + 1
         .SortColumn(iSortIndex) = lCol
      End If
   
      ' Determine which sort order to apply:
      sTag = grdThis.ColumnTag(lCol)
      If (sTag = "") Then
         sTag = "DESC"
 