Get rid of new popup box from reftex - how?

[Colin Baxter]

I notice that emacs-29.0.5 presents me with a popup confirmation dialog
box whenever I use reftex to save a local bibtex file. How can I get
back to receiving the confirmation message in the emacs' echo buffer?
This used to be the procedure up to and including emacs-28.1. Why the
change? For me, popups are a nuisance since they often involve having to
use the mouse and can get lost in full-screen emacs.

Thanks.

Best wishes,

Colin Baxter.