code: protected List<Boolean> getVisibilities(String key) {
  
          List<Boolean> result = new ArrayList<Boolean>();
          for (CmsContainerConfiguration config : m_parentConfigurations) {
              result.add(config.getVisibility().get(key));
          }
          return result;
      }
docs: Gets the list of visibilities for a given key in all the tree levels.<p>
  
  @param key the key for which the visibilities should be returned
  
  @return the list of visibilities, from top to bottom