Apparently I downvoted an answer last night when I intended to upvote it. The only thing I can think is that I may have followed a link, then backed up to the page and voted (or attempted to vote) before my browser fully compiled the math on the page, so that my click registered in a different place than I intended (the compilation causes a small vertical shift in the view, which on the page in questions is of about the distance between the downvote and upvote buttons...). Now the system tells me my vote is too old to change, unless the answer is edited. I feel a little odd editing the answer just to remove my downvote. Is there a better way to remove my downvote?