src/Pure/ML/ml_statistics.scala

   def chart(arg: (String, Iterable[String])): JFreeChart = chart(arg._1, arg._2)
 
   def standard_frames: Unit =
     ML_Statistics.standard_fields.map(chart(_)).foreach(c =>
       Swing_Thread.later {
-        new Frame { contents = Component.wrap(new ChartPanel(c)); visible = true }
+        new Frame {
+          iconImage = Isabelle_System.get_icon().getImage
+          contents = Component.wrap(new ChartPanel(c))
+          visible = true
+        }
       })
 }