Well, I'm surprised that this hasn't been mentioned yet as it's been an issue for a good while. Basically, the search bar doesn't update (it stays as a single white horizontal line), but you can still type to search for stuff.

Hm, could you provide me with a screenshot of what you mean? I'm not doing anything special with the search (except auto-focusing it) and can't see any issues with it in my environment.

As you can see, I have searched for Cobblestone and the search bar remains the same:

Interesting...

I'm going to release a new build reasonably soon (probably today) with an updated dependency on JEI. Let's hope it'll work then, as it does for me in the dev environment.