code: private void createMaintenanceScheduleControl() {
          schedule = new TextFieldBuilder(Action.MAINTENANCE_WINDOW_SCHEDULE_LENGTH)
                  .id(UIComponentIdProvider.MAINTENANCE_WINDOW_SCHEDULE_ID)
                  .caption(i18n.getMessage("caption.maintenancewindow.schedule")).validator(new CronValidator())
                  .prompt("0 0 3 ? * 6").required(true, i18n).buildTextComponent();
          schedule.addTextChangeListener(new CronTranslationListener());
      }
docs: Text field to specify the schedule.