docs: protected IPortletWindowId parsePortletWindowIdSuffix(
              HttpServletRequest request,
              final String prefix,
              final Set<String> additionalPortletIds,
              final String name) {
          // See if the parameter name has an additional separator
          final int windowIdStartIdx = name.indexOf(SEPARATOR, prefix.length());
          if (windowIdStartIdx < (prefix.length() + SEPARATOR.length()) - 1) {
              return null;
          }
  
          // Extract the windowId string and see if it was listed as an additional windowId
          final String portletWindowIdStr = name.substring(windowIdStartIdx + SEPARATOR.length());
          if (additionalPortletIds.contains(portletWindowIdStr)) {
              try {
                  return this.portletWindowRegistry.getPortletWindowId(request, portletWindowIdStr);
              } catch (IllegalArgumentException e) {
                  this.logger.warn(
                          "Failed to parse portlet window id: "
                                  + portletWindowIdStr
                                  + " null will be returned",
                          e);
              }
          }
  
          return null;
      }