I was having the same problem.
I entered the FlexForm forum, and then typed a few keywords to search. I selected one — and it kept making me enter the license key, to which nothing would happen. No error, nothing. Then I read the above that it only works within the forum. There was no theme names in the search result as the entry above reads.
HOWEVER, it appears when you search, it searches ALL forums, not the one you’re registered for. I would recommend fixing it so that when you search, it only searches within the theme forum I’m allowed to see.