code: private void initOptionGroup(OptionGroup optGroup) {
  
          optGroup.addStyleName(ValoTheme.OPTIONGROUP_HORIZONTAL);
          optGroup.setNullSelectionAllowed(false);
          optGroup.addItem("true");
          optGroup.addItem("false");
          optGroup.addItem("");
          CmsWorkplaceMessages wpMessages = OpenCms.getWorkplaceManager().getMessages(A_CmsUI.get().getLocale());
          optGroup.setItemCaption("true", wpMessages.key(org.opencms.workplace.commons.Messages.GUI_LABEL_TRUE_0));
          optGroup.setItemCaption("false", wpMessages.key(org.opencms.workplace.commons.Messages.GUI_LABEL_FALSE_0));
          optGroup.setItemCaption("", wpMessages.key(org.opencms.workplace.commons.Messages.GUI_SECURE_NOT_SET_0));
      }
docs: Fills the selection widget with the options 'True', 'False' and 'Not set'.<p>
  
  @param optGroup the option group to initialize