Cannot select more than one term per vocab in advanced search

This should probably be set to multiple select to allow for selecting multiple terms to search from one vocab listing when using advanced search:

Around line 370ish, changing the 0 to a 1 will make the lists multiple select:

 if ($vocabularies) {
        foreach ($vocabularies as $vocabulary) {
          $group .= _taxonomy_term_select($vocabulary->name, 'taxonomy', $edit['taxonomy'], $vocabulary->vid, '', 0, '<'. t('all categories') .'>');