src/Tools/Graphview/visualizer.scala

       Shapes.Cardinal_Spline_Edge.paint(gfx, visualizer, edge)
     for (node <- visible_graph.keys_iterator)
       Shapes.paint_node(gfx, visualizer, node)
   }
 
-  var alphabetic_order: Boolean = false
   var current_node: Option[Graph_Display.Node] = None
 
   object Selection
   {
     // owned by GUI thread