Hi. I've added the code to the htaccess file, cleaned cache and I've created a new page, a 500 error was shown after the page creation. Still not working, I can't see the complete list of pages. I tried removing the new page, cleaning cache again and it didn't work.
On the other hand, I don't know if this information can help you, but when I try to search any text of a page name that exists, initially I can't see all the pages (normally I have 4 pages, for 4 languages), but if I change the number of results to display (5, 10, 15, 20, ... 200, 500) I can see all the 4 pages.