She's got nothing against vertical surfaces--the back of my chair is evidence of that. And they have shared a scratching post for years and years, so it isn't a territorial thing. The one difference is that this one is a sisal sheet around the post, rather than rope (the rope was always shredding and shedding fibers). I did see her scratch it briefly, this morning, after I yelled at her for scratching the ottoman and took her over to the new scratching post. Hopefully she gets used to it.