Problems with theme()

Hi,

There seems to be a problem with how magic_tabs handles the drupal theme function. For example, I am trying to display a users interests tag cloud inside of a tab, using the interest and tagadelic modules respectively. Here is the function i'm using inside of my custom callback:

function dload_profile_tags_tab($uid,$account) {
	$result = db_query("SELECT i.counter AS count, t.tid, t.name, t.vid, t.weight FROM {interests} i, {term_data} t WHERE t.tid = i.tid AND i.uid = '%s' ORDER BY t.name DESC", $uid);
	$tags = tagadelic_build_weighted_tags($result, $steps = 6);
	$output = theme('tagadelic_weighted', $tags);
	$output .= '[+]';
	return $output;

If I remove the '$output .= '[+]';', inserted to fix the problem, magic_tabs doesn't expand properly to encapsulate the content. I noticed this with views_tagadelic too, so come to think of it, this may be related to the combined use of magic_tabs/tagadelic (or its use of theme()/CSS).

Best regards,
.