src/Pure/System/isabelle_process.ML

   let
     val _ = OS.Process.sleep (seconds 0.5);  (*yield to raw ML toplevel*)
     val _ = Output.physical_stderr Symbol.STX;
 
     val _ = Printer.show_markup_default := true;
-    val _ = quick_and_dirty := false;
     val _ = Context.set_thread_data NONE;
     val _ =
       Unsynchronized.change print_mode
         (fn mode => (mode @ default_modes1) |> fold (update op =) default_modes2);