Just some more information, from comment-template.php
This is what every reply to a comment link is referencing:
$link = "<a rel='nofollow' class='comment-reply-link' href='" . get_permalink($post->ID) . "#$respond_id' onclick='return addComment.moveForm(\"$add_below-$post->ID\", \"0\", \"$respond_id\", \"$post->ID\")'>$reply_text</a>";
For example (this is what firebug is saying is being called in html to reply to a comment with id 11):
<a class="comment-reply-link" onclick="return addComment.moveForm("comment-11", "11", "respond", "11")" href="/url of post/?replytocom=11#respond">Reply> </a>
Is there any reason why the reply field will only be displayed in the first tab and not displayed in the other tabs.