diff --git a/src/Tools/jEdit/src/theories_dockable.scala b/src/Tools/jEdit/src/theories_dockable.scala
--- a/src/Tools/jEdit/src/theories_dockable.scala
+++ b/src/Tools/jEdit/src/theories_dockable.scala
@@ -1,301 +1,301 @@
 /*  Title:      Tools/jEdit/src/theories_dockable.scala
     Author:     Makarius
 
 Dockable window for theories managed by prover.
 */
 
 package isabelle.jedit
 
 
 import isabelle._
 
 import scala.swing.{Button, TextArea, Label, ListView, Alignment,
   ScrollPane, Component, CheckBox, BorderPanel, BoxPanel, Orientation}
 import scala.swing.event.{MouseClicked, MouseMoved}
 
 import java.awt.{BorderLayout, Graphics2D, Color, Point, Dimension}
 import javax.swing.{JList, BorderFactory, UIManager}
 import javax.swing.border.{BevelBorder, SoftBevelBorder}
 
 import org.gjt.sp.jedit.{View, jEdit}
 
 
 class Theories_Dockable(view: View, position: String) extends Dockable(view, position) {
   /* status */
 
-  private val status = new ListView(List.empty[Document.Node.Name]) {
+  private val status = new ListView[Document.Node.Name](Nil) {
     background = {
       // enforce default value
       val c = UIManager.getDefaults.getColor("Panel.background")
       new Color(c.getRed, c.getGreen, c.getBlue, c.getAlpha)
     }
     listenTo(mouse.clicks)
     listenTo(mouse.moves)
     reactions += {
       case MouseClicked(_, point, _, clicks, _) =>
         val index = peer.locationToIndex(point)
         if (index >= 0) {
           val index_location = peer.indexToLocation(index)
           val a = in_required(index_location, point)
           val b = in_required(index_location, point, document = true)
           if (a || b) {
             if (clicks == 1) {
               Document_Model.node_required(listData(index), toggle = true, document = b)
             }
           }
           else if (clicks == 2) PIDE.editor.goto_file(true, view, listData(index).node)
         }
       case MouseMoved(_, point, _) =>
         val index = peer.locationToIndex(point)
         val index_location = peer.indexToLocation(index)
         if (index >= 0 && in_required(index_location, point)) {
           tooltip = "Mark as required for continuous checking"
         }
         else if (index >= 0 && in_required(index_location, point, document = true)) {
           tooltip = "Mark as required for continuous checking, with inclusion in document"
         }
         else if (index >= 0 && in_label(index_location, point)) {
           val name = listData(index)
           val st = nodes_status.overall_node_status(name)
           tooltip =
             "theory " + quote(name.theory) +
               (if (st == Document_Status.Overall_Node_Status.ok) "" else " (" + st + ")")
         }
         else tooltip = null
     }
   }
   status.peer.setLayoutOrientation(JList.HORIZONTAL_WRAP)
   status.peer.setVisibleRowCount(0)
   status.selection.intervalMode = ListView.IntervalMode.Single
 
   set_content(new ScrollPane(status))
 
 
   /* controls */
 
   def phase_text(phase: Session.Phase): String = "Prover: " + phase.print
 
   private val session_phase = new Label(phase_text(PIDE.session.phase))
   session_phase.border = new SoftBevelBorder(BevelBorder.LOWERED)
   session_phase.tooltip = "Status of prover session"
 
   private def handle_phase(phase: Session.Phase): Unit = {
     GUI_Thread.require {}
     session_phase.text = " " + phase_text(phase) + " "
   }
 
   private val purge = new GUI.Button("Purge") {
     tooltip = "Restrict document model to theories required for open editor buffers"
     override def clicked(): Unit = PIDE.editor.purge()
   }
 
   private val continuous_checking = new JEdit_Options.continuous_checking.GUI
   continuous_checking.focusable = false
 
   private val logic = JEdit_Sessions.logic_selector(PIDE.options, autosave = true)
 
   private val controls =
     Wrap_Panel(List(purge, continuous_checking, session_phase, logic))
 
   add(controls.peer, BorderLayout.NORTH)
 
 
   /* component state -- owned by GUI thread */
 
   private var nodes_status = Document_Status.Nodes_Status.empty
   private var theory_required: Set[Document.Node.Name] = Document_Model.required_nodes(false)
   private var document_required: Set[Document.Node.Name] = Document_Model.required_nodes(true)
 
   private class Geometry {
     private var location: Point = null
     private var size: Dimension = null
 
     def in(location0: Point, p: Point): Boolean =
       location != null && size != null && location0 != null && p != null && {
         val x = location0.x + location.x
         val y = location0.y + location.y
         x <= p.x && p.x < x + size.width &&
         y <= p.y && p.y < y + size.height
       }
 
     def update(new_location: Point, new_size: Dimension): Unit = {
       if (new_location != null && new_size != null) {
         location = new_location
         size = new_size
       }
     }
   }
 
   private def in_required(location0: Point, p: Point, document: Boolean = false): Boolean =
     Node_Renderer_Component != null && {
       val required =
         if (document) Node_Renderer_Component.document_required
         else Node_Renderer_Component.theory_required
       required.geometry.in(location0, p)
     }
 
   private def in_label(location0: Point, p: Point): Boolean =
     Node_Renderer_Component != null && Node_Renderer_Component.label_geometry.in(location0, p)
 
   private class Required extends CheckBox {
     val geometry = new Geometry
     opaque = false
     override def paintComponent(gfx: Graphics2D): Unit = {
       super.paintComponent(gfx)
       geometry.update(location, size)
     }
   }
 
   private object Node_Renderer_Component extends BorderPanel {
     opaque = true
     border = BorderFactory.createEmptyBorder(2, 2, 2, 2)
 
     var node_name: Document.Node.Name = Document.Node.Name.empty
 
     val theory_required = new Required
     val document_required = new Required
 
     val label_geometry = new Geometry
     val label: Label = new Label {
       background = view.getTextArea.getPainter.getBackground
       foreground = view.getTextArea.getPainter.getForeground
       opaque = false
       xAlignment = Alignment.Leading
 
       override def paintComponent(gfx: Graphics2D): Unit = {
         def paint_segment(x: Int, w: Int, color: Color): Unit = {
           gfx.setColor(color)
           gfx.fillRect(x, 0, w, size.height)
         }
 
         paint_segment(0, size.width, background)
         nodes_status.get(node_name) match {
           case Some(node_status) =>
             val segments =
               List(
                 (node_status.unprocessed, PIDE.options.color_value("unprocessed1_color")),
                 (node_status.running, PIDE.options.color_value("running_color")),
                 (node_status.warned, PIDE.options.color_value("warning_color")),
                 (node_status.failed, PIDE.options.color_value("error_color"))
               ).filter(_._1 > 0)
 
             segments.foldLeft(size.width - 2) {
               case (last, (n, color)) =>
                 val w = (n * ((size.width - 4) - segments.length) / node_status.total) max 4
                 paint_segment(last - w, w, color)
                 last - w - 1
               }
 
           case None =>
             paint_segment(0, size.width, PIDE.options.color_value("unprocessed1_color"))
         }
         super.paintComponent(gfx)
 
         label_geometry.update(location, size)
       }
     }
 
     def label_border(name: Document.Node.Name): Unit = {
       val st = nodes_status.overall_node_status(name)
       val color =
         st match {
           case Document_Status.Overall_Node_Status.ok =>
             PIDE.options.color_value("ok_color")
           case Document_Status.Overall_Node_Status.failed =>
             PIDE.options.color_value("failed_color")
           case _ => label.foreground
         }
       val thickness1 = if (st == Document_Status.Overall_Node_Status.pending) 1 else 3
       val thickness2 = 4 - thickness1
 
       label.border =
         BorderFactory.createCompoundBorder(
           BorderFactory.createLineBorder(color, thickness1),
           BorderFactory.createEmptyBorder(thickness2, thickness2, thickness2, thickness2))
     }
 
     val required = new BoxPanel(Orientation.Horizontal)
     required.contents += theory_required
     // FIXME required.contents += document_required
 
     layout(required) = BorderPanel.Position.West
     layout(label) = BorderPanel.Position.Center
   }
 
   private class Node_Renderer extends ListView.Renderer[Document.Node.Name] {
     def componentFor(
       list: ListView[_ <: isabelle.Document.Node.Name],
       isSelected: Boolean,
       focused: Boolean,
       name: Document.Node.Name,
       index: Int
     ): Component = {
       val component = Node_Renderer_Component
       component.node_name = name
       component.theory_required.selected = theory_required.contains(name)
       component.document_required.selected = document_required.contains(name)
       component.label_border(name)
       component.label.text = name.theory_base_name
       component
     }
   }
   status.renderer = new Node_Renderer
 
   private def handle_update(
     domain: Option[Set[Document.Node.Name]] = None,
     trim: Boolean = false
   ): Unit = {
     GUI_Thread.require {}
 
     val snapshot = PIDE.session.snapshot()
 
     val (nodes_status_changed, nodes_status1) =
       nodes_status.update(
         PIDE.resources, snapshot.state, snapshot.version, domain = domain, trim = trim)
 
     nodes_status = nodes_status1
     if (nodes_status_changed) {
       status.listData =
         (for {
           (name, node_status) <- nodes_status1.present.iterator
           if !node_status.is_suppressed && node_status.total > 0
         } yield name).toList
     }
   }
 
 
   /* main */
 
   private val main =
     Session.Consumer[Any](getClass.getName) {
       case phase: Session.Phase =>
         GUI_Thread.later { handle_phase(phase) }
 
       case _: Session.Global_Options =>
         GUI_Thread.later {
           continuous_checking.load()
           logic.load ()
           theory_required = Document_Model.required_nodes(false)
           document_required = Document_Model.required_nodes(true)
           status.repaint()
         }
 
       case changed: Session.Commands_Changed =>
         GUI_Thread.later { handle_update(domain = Some(changed.nodes), trim = changed.assignment) }
     }
 
   override def init(): Unit = {
     PIDE.session.phase_changed += main
     PIDE.session.global_options += main
     PIDE.session.commands_changed += main
 
     handle_phase(PIDE.session.phase)
     handle_update()
   }
 
   override def exit(): Unit = {
     PIDE.session.phase_changed -= main
     PIDE.session.global_options -= main
     PIDE.session.commands_changed -= main
   }
 }