diff --git a/src/Tools/jEdit/src/document_dockable.scala b/src/Tools/jEdit/src/document_dockable.scala
--- a/src/Tools/jEdit/src/document_dockable.scala
+++ b/src/Tools/jEdit/src/document_dockable.scala
@@ -1,244 +1,271 @@
 /*  Title:      Tools/jEdit/src/document_dockable.scala
     Author:     Makarius
 
 Dockable window for document build support.
 */
 
 package isabelle.jedit
 
 
 import isabelle._
 
 import java.awt.BorderLayout
 import java.awt.event.{ComponentEvent, ComponentAdapter}
 
 import scala.swing.{ScrollPane, TextArea, Label, TabbedPane, BorderPanel, Component}
 
 import org.gjt.sp.jedit.{jEdit, View}
 
 
 object Document_Dockable {
-  def document_output(name: String = "document"): Path = {
-    val dir = Path.explode("$ISABELLE_HOME_USER/document_output")
-    if (name.isEmpty) dir else dir + Path.explode(name)
+  /* document output */
+
+  def document_name: String = "document"
+  def document_output_dir(): Path = Path.explode("$ISABELLE_HOME_USER/document_output")
+  def document_output(): Path = document_output_dir() + Path.basic(document_name)
+
+  def view_document(): Unit = {
+    val path = Document_Dockable.document_output().pdf
+    if (path.is_file) Isabelle_System.pdf_viewer(path)
   }
 
+  class Log_Progress extends Progress {
+    def show(text: String): Unit = {}
+
+    private val syslog = PIDE.session.make_syslog()
+
+    private def update(text: String = syslog.content()): Unit = GUI_Thread.require { show(text) }
+    private val delay =
+      Delay.first(PIDE.options.seconds("editor_update_delay"), gui = true) { update() }
+
+    override def echo(msg: String): Unit = { syslog += msg; delay.invoke() }
+    override def theory(theory: Progress.Theory): Unit = echo(theory.message)
+
+    def load(): Unit = {
+      val path = document_output().log
+      val text = if (path.is_file) File.read(path) else ""
+      GUI_Thread.later { delay.revoke(); update(text) }
+    }
+
+    update()
+  }
+
+
+  /* state */
+
   object Status extends Enumeration {
     val WAITING = Value("waiting")
     val RUNNING = Value("running")
     val FINISHED = Value("finished")
   }
 
   sealed case class Result(output: List[XML.Tree] = Nil) {
     def failed: Boolean = output.exists(Protocol.is_error)
   }
 
   object State {
-    val empty: State = State()
+    def empty(): State = State()
     def finish(result: Result): State = State(output = result.output)
   }
 
   sealed case class State(
-    progress: Progress = new Progress,
+    progress: Log_Progress = new Log_Progress,
     process: Future[Unit] = Future.value(()),
     output: List[XML.Tree] = Nil,
-    status: Status.Value = Status.FINISHED
-  )
+    status: Status.Value = Status.FINISHED)
 }
 
 class Document_Dockable(view: View, position: String) extends Dockable(view, position) {
   GUI_Thread.require {}
 
 
   /* component state -- owned by GUI thread */
 
-  private val current_state = Synchronized(Document_Dockable.State.empty)
+  private val current_state = Synchronized(Document_Dockable.State.empty())
 
   private val process_indicator = new Process_Indicator
   private val pretty_text_area = new Pretty_Text_Area(view)
   private val message_pane = new TabbedPane
 
   private def show_state(): Unit = GUI_Thread.later {
     val st = current_state.value
 
     pretty_text_area.update(Document.Snapshot.init, Command.Results.empty, st.output)
 
     st.status match {
       case Document_Dockable.Status.WAITING =>
         process_indicator.update("Waiting for PIDE document content ...", 5)
       case Document_Dockable.Status.RUNNING =>
         process_indicator.update("Running document build process ...", 15)
       case Document_Dockable.Status.FINISHED =>
         process_indicator.update(null, 0)
     }
   }
 
   private def show_page(page: TabbedPane.Page): Unit = GUI_Thread.later {
     message_pane.selection.page = page
   }
 
 
   /* text area with zoom/resize */
 
   override def detach_operation: Option[() => Unit] = pretty_text_area.detach_operation
 
   private val zoom = new Font_Info.Zoom { override def changed(): Unit = handle_resize() }
   private def handle_resize(): Unit = GUI_Thread.require { pretty_text_area.zoom(zoom) }
 
   private val delay_resize: Delay =
     Delay.first(PIDE.options.seconds("editor_update_delay"), gui = true) { handle_resize() }
 
   addComponentListener(new ComponentAdapter {
     override def componentResized(e: ComponentEvent): Unit = delay_resize.invoke()
     override def componentShown(e: ComponentEvent): Unit = delay_resize.invoke()
   })
 
 
   /* progress log */
 
   private val log_area =
     new TextArea {
       editable = false
       font = GUI.copy_font((new Label).font)
     }
   private val scroll_log_area = new ScrollPane(log_area)
 
-  private class Log_Progress extends Progress {
-    private val syslog = PIDE.session.make_syslog()
-
-    private def update(): Unit = {
-      val text = syslog.content()
-      if (text != log_area.text) {
-        log_area.text = text
-        val vertical = scroll_log_area.peer.getVerticalScrollBar
-        vertical.setValue(vertical.getMaximum)
-      }
+  def init_progress(): Document_Dockable.Log_Progress =
+    new Document_Dockable.Log_Progress {
+      override def show(text: String): Unit =
+        if (text != log_area.text) {
+          log_area.text = text
+          val vertical = scroll_log_area.peer.getVerticalScrollBar
+          vertical.setValue(vertical.getMaximum)
+        }
     }
-    update()
-
-    private val delay =
-      Delay.first(PIDE.options.seconds("editor_update_delay"), gui = true) { update() }
-
-    override def echo(msg: String): Unit = { syslog += msg; delay.invoke() }
-
-    override def theory(theory: Progress.Theory): Unit = echo(theory.message)
-  }
 
 
   /* document build process */
 
   private def cancel(): Unit =
     current_state.change { st => st.process.cancel(); st }
 
+  private def init_state(): Unit =
+    current_state.change { _ => Document_Dockable.State(progress = init_progress()) }
+
   private def build_document(): Unit = {
     current_state.change { st =>
       if (st.process.is_finished) {
-        val progress = new Log_Progress()
+        val progress = init_progress()
         val process =
           Future.thread[Unit](name = "document_build") {
             show_page(log_page)
             val res =
               Exn.capture {
                 progress.echo("Start " + Date.now())
                 for (i <- 1 to 200) {
                   progress.echo("message " + i)
                   Time.seconds(0.1).sleep()
                 }
                 progress.echo("Stop " + Date.now())
               }
             val msg =
               res match {
                 case Exn.Res(_) => Protocol.make_message(XML.string("OK"))
                 case Exn.Exn(exn) => Protocol.error_message(XML.string(Exn.message(exn)))
               }
             val result = Document_Dockable.Result(output = List(msg))
             current_state.change(_ => Document_Dockable.State.finish(result))
             show_state()
             show_page(output_page)
           }
         st.copy(progress = progress, process = process, status = Document_Dockable.Status.RUNNING)
       }
       else st
     }
     show_state()
   }
 
-  private def view_document(): Unit = {
-    val path = Document_Dockable.document_output().pdf
-    if (path.is_file) Isabelle_System.pdf_viewer(path)
-  }
-
 
   /* controls */
 
   private val document_session: GUI.Selector[String] =
     new GUI.Selector(JEdit_Sessions.sessions_structure().build_topological_order.sorted) {
       val title = "Session"
     }
 
   private val build_button =
     new GUI.Button("<html><b>Build</b></html>") {
       tooltip = "Build document"
       override def clicked(): Unit = build_document()
     }
 
   private val cancel_button =
     new GUI.Button("Cancel") {
       tooltip = "Cancel build process"
       override def clicked(): Unit = cancel()
     }
 
   private val view_button =
     new GUI.Button("View") {
       tooltip = "View document"
-      override def clicked(): Unit = view_document()
+      override def clicked(): Unit = Document_Dockable.view_document()
     }
 
   private val controls =
     Wrap_Panel(List(document_session, process_indicator.component, build_button,
       view_button, cancel_button))
 
   add(controls.peer, BorderLayout.NORTH)
 
   override def focusOnDefaultComponent(): Unit = build_button.requestFocus()
 
 
   /* message pane with pages */
 
   private val output_controls =
     Wrap_Panel(List(pretty_text_area.search_label, pretty_text_area.search_field, zoom))
 
   private val output_page =
     new TabbedPane.Page("Output", new BorderPanel {
       layout(output_controls) = BorderPanel.Position.North
       layout(Component.wrap(pretty_text_area)) = BorderPanel.Position.Center
     }, "Output from build process")
 
+  private val load_button =
+    new GUI.Button("Load") {
+      tooltip = "Load final log file"
+      override def clicked(): Unit = current_state.value.progress.load()
+    }
+
+  private val log_controls =
+    Wrap_Panel(List(load_button))
+
   private val log_page =
     new TabbedPane.Page("Log", new BorderPanel {
+      layout(log_controls) = BorderPanel.Position.North
       layout(scroll_log_area) = BorderPanel.Position.Center
     }, "Raw log of build process")
 
   message_pane.pages ++= List(log_page, output_page)
 
   set_content(message_pane)
 
 
   /* main */
 
   private val main =
     Session.Consumer[Session.Global_Options](getClass.getName) {
       case _: Session.Global_Options =>
         GUI_Thread.later { handle_resize() }
     }
 
   override def init(): Unit = {
+    init_state()
     PIDE.session.global_options += main
     handle_resize()
   }
 
   override def exit(): Unit = {
     PIDE.session.global_options -= main
     delay_resize.revoke()
   }
 }