src/Tools/jEdit/src/graphview_dockable.scala

       case Exn.Res(proper_graph) =>
         new isabelle.graphview.Main_Panel(proper_graph) {
           override def make_tooltip(parent: JComponent, x: Int, y: Int, body: XML.Body): String =
           {
             val rendering = Rendering(snapshot, PIDE.options.value)
-            new Pretty_Tooltip(view, parent, rendering, x, y, body)
+            new Pretty_Tooltip(view, parent, rendering, x, y, Command.empty_results, body)
             null
           }
         }
       case Exn.Exn(exn) => new TextArea(Exn.message(exn))
     }