I believe templates/fi_divexpand.js is the .script that adds that functionality. Removing the .script calls in bbcode.tpl doesn't work because then it puts the quoted text in the header part of the quote... I assume it's missing a div when the .script call is removed.
Editing fi_divexpand.js affects code and php bbcodes as well. I little testing on my site ended with this that seems to work with minimal editing.
OPEN templates/fi_divexpand.js
FIND: (line 38)
document.write('‹ <a>Select</a> ›‹ <span><a>Expand</a> ›</span></div><div>');
REPLACE WITH] document.write(' </div><div>'); [/code]
*NOTE* - Part of the FIND code posted above is being parsed as html strangely enough... If you do this slight modification, you should A) backup your fi_divexpand.js and B) replace the second to last line of fi_divexpand.js (it's my line 38) with the code posted in the REPLACE WITH: