def fire_action_event
      if header_row?
        if @table_row_sorter
          x = _convert_curpos_to_column
          c = @chash[x]
          # convert to index in data model since sorter only has data_model
          index = c.index
          @table_row_sorter.toggle_sort_order index
          @table_row_sorter.sort
          fire_dimension_changed
        end
      end
      super
    end
def fire_action_event
      if header_row?
        if @table_row_sorter
          x = _convert_curpos_to_column
          c = @chash[x]
          # convert to index in data model since sorter only has data_model
          index = c.index
          @table_row_sorter.toggle_sort_order index
          @table_row_sorter.sort
          fire_dimension_changed
        end
      end
      super
    end
called when ENTER is pressed.
 Takes into account if user is on header_row