needs a little tweak Rated 3 out of 5 stars

it works this way:
http://sub.domain.com/dir/
http://domain.com/

and i think it really should work this way:
http://sub.domain.com/dir/
http://sub.domain.com/
http://domain.com/

This review is for a previous version of the add-on (1.6). 

Resolved in Navigate Up version 2.0

Navigate Up Version 2.0 resolves this problem.