src/Tools/jEdit/src/raw_output_dockable.scala

 
   private val main_actor = actor {
     loop {
       react {
         case result: Isabelle_Process.Result =>
-          if (result.is_stdout)
+          if (result.is_stdout || result.is_stderr)
             Swing_Thread.now { text_area.append(XML.content(result.message).mkString) }
 
         case bad => System.err.println("Raw_Output_Dockable: ignoring bad message " + bad)
       }
     }