Find TMDB ID for Movie Set?

What is the function of the button in sets labeled “Find Tmdbid”?

I’ve tried clicking on it when there is already a set id, and when the set id is blank or zero, but it never seems to do anything but return a message saying no TMDB ID could be found.

But when I right click the movie and select “Search TMDB for movie data”, it will pull up the ID, as well as the rest of the meta data.

Thanks, Carl.