Floating check box under comments, how to get rid of it?

Under the "post comment" button on a post there is a check box with nothing else. Below that, there is a couple of jetpack options with check boxes, to follow the comments or follow the blog. I don't understand what the first empty check box is for, and how to eliminate it. It's really driving me crazy, and I'm considering changing to a new theme if I can't resolve this. Please help! Thanks.