+ MatitaGtkMisc.toggle_widget_visibility
+ ~widget:(self#main#tacticsButtonsHandlebox :> GObj.widget)
+ ~check:self#main#tacticsBarMenuItem;
+ let module Hr = Helm_registry in
+ if not(Hr.get_opt_default Hr.get_bool false "matita.tactics_bar") then
+ self#main#tacticsBarMenuItem#set_active false;