regression: tableselect headers misaligned when #js_select is FALSE

The checkbox column header disappears if #js_select is set to false on a tableselect element. This causes headers not to align with rows. I believe a simple solution could be to add a little piece of code in theme_tableselect().

NOW:

    if ($element['#js_select']) {
      drupal_add_js('misc/tableselect.js');
      array_unshift($header, array('class' => array('select-all')));
    }

CHANGE TO:

    if ($element['#js_select']) {
      drupal_add_js('misc/tableselect.js');
      array_unshift($header, array('class' => array('select-all')));
    } else {
      //Add empty checkbox column header.
      array_unshift($header, array('data' => ''));
    }