def select_default_values
      return if @default_value.nil?
      # NOTE list not yet created
      raise "list has not yet been created" unless @list
      index = node_to_row @default_value
      raise "could not find node #{@default_value}, #{@list}  " unless index
      return unless index
      @current_index = index
      toggle_row_selection
      @default_value = nil
    end
def select_default_values
      return if @default_value.nil?
      # NOTE list not yet created
      raise "list has not yet been created" unless @list
      index = node_to_row @default_value
      raise "could not find node #{@default_value}, #{@list}  " unless index
      return unless index
      @current_index = index
      toggle_row_selection
      @default_value = nil
    end
thanks to shoes, not sure how this will impact since widget has text.
 show default value as selected and fire handler for it
 This is called in repaint, so can raise an error if called on creation
 or before repaint. Just set @default_value, and let us handle the rest.
 Suggestions are welcome.