Remove Citizens2 name via NPC / make it invisible?

Hi, you can find many tutorials on Citizens2, but nowhere a clue how to remove in Minecraft 1.12.2 the annoying name over the head of the NPC. And no, not with & 7 or so, because there's still a gray box over the head of the NPC.

Yes, that works, but I searched this command for a long time, and then by chance came across it. We then did a tutorial about it, you can find it here:

Let's do a like there.