Thickbox title showing up twice

Answer 1

The only thing that makes sense to me is that either something on the "page.php" opens another Thickbox, or that the "page.php" itself contains the extra title.

Since you're not doing anything out of the ordinary with the Thickbox class, I doubt that it is a bug in the actual script.

To debug this, I would first remove the "tag=lists-element" from the query string of the URL, as I don't think that is a Thickbox option (correct me if I'm wrong). That way you can strip it down to the basics and test from there.