src/Tools/Graphview/src/graph_panel.scala

 Graphview Java2D drawing panel.
 */
 
 package isabelle.graphview
 
+import isabelle._
 
 import java.awt.{Dimension, Graphics2D, Point, Rectangle}
 import java.awt.geom.{AffineTransform, Point2D}
 import javax.swing.ToolTipManager
 import scala.swing.{Panel, ScrollPane}