[zottel]

... which will work, of course, but still, it would be nice if OW could present a dialog where I could change the stuff I typed before and save an edited keychain entry if authorisation fails.

This isn't possible for sites like this forum, of course, as OW can't tell whether the login has worked or not. With basic HTTP authorisation, though, the browser gets a back an HTTP header that tells it that the provided login data wasn't correct.

Regards, Christian