fix: hide the priority grid in synchronous mode of rdbgui4sasa

tools/rdbg4sasa/gtkgui.ml

-(* Time-stamp: <modified the 04/01/2023 (at 11:44) by Erwan Jahier> *)
+(* Time-stamp: <modified the 04/01/2023 (at 11:56) by Erwan Jahier> *)
 
 #thread
 #require "lablgtk3"
@@ -418,11 +418,13 @@ let custom_daemon p gtext vbox step_button back_step_button round_button
        pushbox#set_sensitive enabled
        
     | Synchronous | Distributed | Central | LocCentral ->
-       if !daemon_kind = Synchronous then show undo_button
-       else hide undo_button;
+      if !daemon_kind = Synchronous then (
+        show undo_button; hide counter_grid
+      ) else (
+        hide undo_button; show counter_grid
+      );
        (match !oracle_button_ref with Some b -> show b | None -> ());
        show back_step_button; show step_button; show round_button;
-       show counter_grid;
        if not args.salut_mode then show legitimate_button; (* for the time being *)
        hide checkbox_grid; hide pushbox_grid;
   in