Custom themed button won't submit files

If you override theme_button() with something like the following snippet, upload buttons will cease working.

function mytheme_button($element) {
  // Make sure not to overwrite classes.
  if (isset($element['#attributes']['class'])) {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];
  }
  else {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'];
  }

  return '<div class="submit-button"><input type="submit" '. (empty($element['#name']) ? '' : 'name="'. $element['#name'] .'" ')
     .'id="'. $element['#id'] .'" value="'. check_plain($element['#value']) .'" '. drupal_attributes($element['#attributes']) ." /></div>\n";
}

Looked in filefield.js to find something similar to this on lines 80 and 84:

$enabledFields = $(this).parent().parent().find('input.form-file');

I'm guessing we can change that to use the parents() jQuery function and it'll fix it. Don't have the time right now to roll a patch but will if no one else gets to it first.