DVD Extras

I wanted to try adding some of the DVD extras to my library. I grabbed "Antitrust" and ripped one of the extras. I followed the naming and folder conventions at https://support.plex.tv/hc/en-us/articles/200220677.

I first tried this:
/Movies
/Antitrust (2001)
Antitrust (2001).m4v
Cracking the Code-featurette.m4v

I then tried this:
/Movies
/Antitrust (2001)
Antitrust (2001).m4v
/Featurettes
Cracking the Code.m4v

I have local media assets checked and at the top.

Both ways it showed as a separate movie in my library. Am I missing something?

Thanks