"Broke" two of ours but it transpired they'd only come off the teeny, tiny, Tonka toy lugs holding them in place. About ten minutes of fiddling and I managed to get them both hooked back in and working again - although the "secret" seems to not close them completely so theres no pressure needed to swing them open when required - like the screen washer jets, cheap and nasty. Some comments here, https://www.fiatforum.com/panda/200716-how-remove-broken-air-vent.html