Thread:Extension talk:WYSIWYG/Cancelling an edit causes a 404 page not found error due to the index dot php being removed from the URL

When I cancel an edit, the URL drops the index dot php causing a 404 page not found error. This is caused by the extension, and disabling it by commenting out the require once statement resolves the issue. Please advise. Using version 1.20.2 mediawiki.