public function action_form_comment( $form ) {
                $form->append( 'fieldset','commenterinfo', _t( 'your contact information' ) );
                $form->move_before( $form->commenterinfo, $form->commenter );
                $form->commenter->move_into( $form->commenterinfo );
                $form->email->move_into( $form->commenterinfo );
                $form->url->move_into( $form->commenterinfo );
                $form->append( 'fieldset','contentbox', _t( 'your comment' ) );
                $form->move_before( $form->contentbox, $form->content);
                $form->content->move_into($form->contentbox);
                $form->submit->caption = 'submit comment'; // you would expect it to be value. I did.
        }