code: public void initWorkplaceCssUris(CmsModuleManager moduleManager) {
  
          Set<String> cssUris = new HashSet<String>();
          for (CmsModule module : moduleManager.getAllInstalledModules()) {
              String param = module.getParameter(WORKPLACE_CSS_PARAM);
              if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(param)) {
                  cssUris.add(param);
              }
          }
          File cssFile = new File(
              OpenCms.getSystemInfo().getAbsoluteRfsPathRelativeToWebApplication(
                  CmsStringUtil.joinPaths("resources", TOOLBAR_CSS)));
          if (cssFile.exists()) {
              cssUris.add(TOOLBAR_CSS);
          }
          m_workplaceCssUris = Collections.unmodifiableSet(cssUris);
      }
docs: Initializes the additional workplace CSS URIs.<p>
  They will be taken from the module parameter 'workplace-css' if present in any module.<p>
  
  @param moduleManager the module manager instance