docs: public boolean isHiddenNavigationEntry() {
  
          if (m_isHiddenNavigationEntry == null) {
              // use "lazy initializing"
              String navInfo = getProperties().get(CmsPropertyDefinition.PROPERTY_NAVINFO);
              m_isHiddenNavigationEntry = Boolean.valueOf(CmsClientSitemapEntry.HIDDEN_NAVIGATION_ENTRY.equals(navInfo));
          }
          return m_isHiddenNavigationEntry.booleanValue();
      }