src/Pure/Interface/proof_general.ML

 in
 
 fun setup_messages () =
  (writeln_fn := message "output" "" "" "";
   priority_fn := message "information" (oct_char "360") (oct_char "361") "";
-  tracing_fn := message "tracing" (oct_char "360") (oct_char "361") (oct_char "375");
+  tracing_fn := message "tracing" (oct_char "360" ^ oct_char "375") (oct_char "361") "";
   warning_fn := message "warning" (oct_char "362") (oct_char "363") "### ";
   error_fn := message "error" (oct_char "364") (oct_char "365") "*** ");
 
 fun tell_clear_goals () = notify "Proof General, please clear the goals buffer.";
 fun tell_clear_response () = notify "Proof General, please clear the response buffer.";