I recently found that the top navigation links in a SharePoint site don’t highlight the active tab. After a few tries I realised that the links in the Url field need to be “clean”.

I had initially a Url with %20 characters in there and other with / at the end of the string.

Once I removed them from the Url field, the active tab started working.

Hopefully this helps someone.

(PS: I was using sp2 in this environment)