remote_form_for works only in IE, not Firefox

Any idea around ? Does some of you had any problem with Ajax and Firefox

Just to be clear about the problem : the fields of the form are not
posted (or at least their values are not in params[]) correctly with
FireFox while it works fine with IE

Is the request being submitted to Rails with Firefox? Or is nothing happening at all? And if the latter, are you using Rico? Try removing Rico and see if it solves the problem.