Following today’s updates, I experimentally tried changing my display name, and it won’t let me change back to the old name. It says that name is taken.
This is by design. When changing usernames on this site, it compares to the old site to see if the name is taken (to prevent people from “stealing” usernames.)
We can fix this, but you’ll need to contact me privately. Pop me a message. What we’ll basically have to do is I’ll go in and change your name on the old site to something else (anything will do, I usually add a few numbers to it) so that your username is “freed up.” You can then go back and change the one here to the original, then we can go back to the old site and change it back to what it should be. It’s a one-way restriction. (The old site doesn’t check the new one, only its existing database.)
I endorse Heather’s workaround!
As do I!