src/Tools/jEdit/src/jedit/isabelle_sidekick.scala

   def parser(data: SideKickParsedData, model: Document_Model)
   {
     import Isabelle_Sidekick.int_to_pos
 
     val root = data.root
-    val doc = model.snapshot().node  // FIXME cover all nodes (!??)
+    val doc = Swing_Thread.now { model.snapshot().node }  // FIXME cover all nodes (!??)
     for {
       (command, command_start) <- doc.command_range(0)
       if command.is_command && !stopped
     }
     {

   def parser(data: SideKickParsedData, model: Document_Model)
   {
     import Isabelle_Sidekick.int_to_pos
 
     val root = data.root
-    val snapshot = model.snapshot()  // FIXME cover all nodes (!??)
+    val snapshot = Swing_Thread.now { model.snapshot() }  // FIXME cover all nodes (!??)
     for ((command, command_start) <- snapshot.node.command_range(0) if !stopped) {
       root.add(snapshot.document.current_state(command).markup_root.swing_tree((node: Markup_Node) =>
           {
             val content = command.source(node.start, node.stop).replace('\n', ' ')
             val id = command.id