AX and OAuth are working fine now, thanks.
I'm not so sure about the UI extension though. The "popup" option seems to have no effect, and I believe the login page UI is different from before.
It now shows the Google and Facebook buttons, which weren't there before, and I don't think they make much sense in the context of an OpenID login by a user who has just explicitly chosen to login via their Yahoo account.
And the window now automatically resizes itself to a fixed size, even if it was already more than big enough. This is a problem for us and probably others, as the page that we show after login is designed for a certain minimum size. And it's very annoying on sites like stackoverflow.com that open the OpenID login in the same browser window, instead of in a popup.