Create a loading bar for the searching action in the categories, so that the user can see how long s/he shall wait.
Background: I just was using the tool with a quite complex topic: health. It took quite a while to get any examples. The only thing for me to know, that it's taking time was "Bitte warten". But I felt closing it, because it's taking too long and I didn't know if it's just stuck or something else.
(Just an Idea from my side and would be awesome to have it inside)