code: private void createMaintenanceDurationControl() {
          duration = new TextFieldBuilder(Action.MAINTENANCE_WINDOW_DURATION_LENGTH)
                  .id(UIComponentIdProvider.MAINTENANCE_WINDOW_DURATION_ID)
                  .caption(i18n.getMessage("caption.maintenancewindow.duration")).validator(new DurationValidator())
                  .prompt("hh:mm:ss").required(true, i18n).buildTextComponent();
      }
docs: Text field to specify the duration.