Well, it's also possible that it existed before and I just never noticed, LOL! (It is a rather tiny visual glitch that you almost have to be looking for to have it brought to one's attention.) I was looking particularly to see if everything looked right because of the post, and that's when I noticed it. But if you weren't aware of this existing before (and I would assume someone else would have said something), then I wish you the best of luck finding the change that caused it. :)

Also, I should've taken a picture of the comment box because I'm seeing another issue there (which I was too focused on commenting the first time to have it in my conscious awareness) - the More Options button is insisting on hanging down on a second line, no matter how wide I drag the comment box. And unlike the person above who said it was DWTools that borked things up, I do not have any extensions on my Firefox that should be rearranging how DW looks at all. Let me know if you need a screenshot of this or if my description of the issue is clear enough.