Hello, is there something I'm missing to make this block work?

I created a couple of fields and allowed to be filtered.

 

Then when I go to configure the block or widget, I'm expected to see some database selection at least, but it only shows this:

 

I save and the block disappears from visibility.

In other words, it doesn't seem to work. Is it meant to work with any type of field?

Am I missing some step in between?

Any help will be much appreciated.

Well, it must have been a caching problem, because suddenly the block is showing now. 🙂