def select_values values
      return unless values
      values.each do |val|
        row = @list.index val
        add_row_selection_interval row, row unless row.nil?
      end
    end
def select_values values
      return unless values
      values.each do |val|
        row = @list.index val
        add_row_selection_interval row, row unless row.nil?
      end
    end
selects all rows with the values given, leaving existing selections
 intact. Typically used after accepting search criteria, and getting a list of values
 to select (such as file names). Will not work with tables (array or array)