src/Tools/jEdit/src/document_dockable.scala

     val document_session = PIDE.editor.document_session()
     if (document_session.is_vacuous) true
     else if (document_session.is_pending) false
     else {
       run_process(reset_pending = true) { progress =>
+        output_process(progress)
         show_page(output_page)
+
         val result = Exn.capture { document_build(document_session, progress) }
         val msgs =
           result match {
             case Exn.Res(_) =>
               List(Protocol.writeln_message("OK"))