Configure Route Filter as below and it doesn't work. (I know, I know, the route is an add-on route but route filter should work with all kind of routes right?) I have track down the issues and problem lies in XenForo_Link::translateRouteFilterToRegex. This method does not perform urldecode for the target route ($to variable). I added this simple line before the return statement and everything works as expected. PHP: $to = urldecode($to); Actually there are 2 approaches to fix this issue. The above is the first one. Another is to require admin to enter "tags/blah(space)blah(space)blah/" in "Find Route" and perform urlencode when build links. I prefer the first approach because it seems to use less server resources.