Well that skin was built a long time ago in a galaxy far far away… oh wait. Anyway, it's not been properly maintained to keep up with changes in the base code so it's a wonder it even worked as well as it did all this time.
I didn't even enable it. Just logged in one day and it was automatically on and was like "sweet, new look." Been using it ever since and loving it. I only noticed there was another skin when people kept saying the post count was right in the thread and I never saw it.