# File gtk/sample/gtk-demo/changedisplay.rb, line 138
    def create_display_frame
      frame, tree_view, button_vbox = create_frame('Display')

      button = left_align_button_new('_Open...')
      button.signal_connect('clicked') do
        open_display_cb
      end
      button_vbox.pack_start(button, false, false, 0)

      button = left_align_button_new('_Close')
      button.signal_connect('clicked') do
        if @current_display
          @current_display.close
        end
      end
      button_vbox.pack_start(button, false, false, 0)

      @display_model = Gtk::ListStore.new(String, Gdk::Display)
      tree_view.model = @display_model

      column = Gtk::TreeViewColumn.new('Name',
                                       Gtk::CellRendererText.new,
                                       {'text' => DISPLAY_COLUMN_NAME})
      tree_view.append_column(column)

      selection = tree_view.selection
      selection.signal_connect('changed') do
        display_changed_cb(selection)
      end

      return frame
    end