jhfarr - Thank you for the correction (please note I asked you if it was working :) ). I've never actually used drag text, since I work in WordPress with the distraction free editor at full sized, which is not that uncommon. When I need to copy content over, I use copy/paste.
What one man sees as required is novel to another. That one was new to me.
I went and made a ticket for this: https://core.trac.wordpress.org/ticket/27880
I don't know what the solution will be for that one, though. I'm surprised no one on WordPress.com (who's been testing this for longer) caught it either.
I'm marking this resolved because there's a trac ticket out, and that's how we keep sane.