I've never had trouble seeing Yellow-throated Martens - they're insanely active and bouncy most of the time.
This is a different exhibit to the one they were in when I went to Nuremberg - looks very good.
(While Yellow-throated and Pine Martens don't give me any trouble, despite many attempts at various zoos I've still never seen a Beech Marten (Martes foina) - the things hate me! Saw a roadkill one recently in the Czech Republic - getting closer!)