More of comment... If you're following along with the first video, helps to make sure that you have the X symmetry on, otherwise, it doesn't do both sides ;)
Don't worry @theluthier , you already mentioned it (as a written comment) in the video.
Wow! Didn't expect a response so fast with the holidays :D It wasn't on by default on mine, I don't think. If it was a comment, I must not have seen it.
But you might not be the only one, so thanks for mentioning it :)