diff -r f53a8f73b40f -r e0d98ff3c0db src/Tools/jEdit/src/graphview_dockable.scala
--- a/src/Tools/jEdit/src/graphview_dockable.scala	Mon Oct 08 12:02:32 2012 +0200
+++ b/src/Tools/jEdit/src/graphview_dockable.scala	Mon Oct 08 12:40:35 2012 +0200
@@ -11,7 +11,7 @@
 import isabelle._
 
 import java.awt.BorderLayout
-import javax.swing.JPanel
+import javax.swing.{JPanel, JComponent}
 
 import scala.actors.Actor._
 
@@ -41,7 +41,15 @@
   {
     graphview.removeAll()
     graphview.setLayout(new BorderLayout)
-    val panel = new isabelle.graphview.Main_Panel(isabelle.graphview.Model.decode_graph(graph))
+    val panel =
+      new isabelle.graphview.Main_Panel(isabelle.graphview.Model.decode_graph(graph)) {
+        override def make_tooltip(parent: JComponent, x: Int, y: Int, body: XML.Body): String =
+        {
+          val rendering = Isabelle_Rendering(current_snapshot, Isabelle.options.value)
+          new Pretty_Tooltip(view, parent, rendering, x, y, body)
+          null
+        }
+      }
     graphview.add(panel.peer, BorderLayout.CENTER)
   }