missing style name in effect summary for 'reuse' effect

When the 'Reuse cropped style' effect is applied, the summary for the image style says:

> Manual Crop: Reuse cropped style (using the crop of )

It looks like there should be another style name there but there isn't.

This is because of this code:

  return '(' . t('using the crop of @style', array('@style' => _manualcrop_image_style_label($variables['data']['reuse_crop_style']))) . ')';

There is no property $variables['data']['reuse_crop_style'] set in $variables.