src/Tools/VSCode/src/server.scala

           case Protocol.Hover(id, node_pos) => hover(id, node_pos)
           case Protocol.GotoDefinition(id, node_pos) => goto_definition(id, node_pos)
           case _ => channel.log("### IGNORED")
         }
       }
-      catch { case exn: Throwable => channel.log("*** ERROR: " + Exn.message(exn)) }
+      catch { case exn: Throwable => channel.error_message(Exn.message(exn)) }
     }
 
     @tailrec def loop()
     {
       channel.read() match {