I've renamed a prevalue, and all the pages that had that prevalue selected now appear to have the renamed value selected, in the Umbraco back office.  We also have a search form (Examine) at the front end which allows you to filter using a drop down list of these prevalues - again, the prevalue I edited appears renamed in the list - so far so good...

...But if I use this search form to filter by the renamed value, it doesn't return anything (if I edit the querystring in my browser to match the old prevalue, then all the pages appear).  Only when I re-save and publish an individual page (without making any changes to it) does it appear in the search results filtered by the new pre-value.  I've tried rebuilding the Examine search index but that didn't help.

It seems the index still holds the old pre-value name for a given page until that page is re-published.  Please could someone explain why this is happening and if there is any way to update all these pages in the search index without painstakingly re-publishing every page?

Thanks!