For some funny reason the main field in the comment box disappears. Actually, first it is there, then it is gone.
Even more funny is that I've used exactly the same settings and equal comments.php files both here (where the trouble is) and here (where it works fine).
Notice, too, that the bolding is different in the two sites. (OK, it appears to be the same site, but based on two different WP installations.)
It looks exactly the same in Firefox, Opera and Safari.
Thanks a lot - and Happy New Year to everybody!