Can anyone who's been using the developers preview of Photos for Mac answer this question for me? I've been wondering how Photos for Mac handles the hierarchical keywords used in Aperture. I'm not overly bothered about losing the structure, but it will be annoying for Photos to 'ignore' all the keywords other than the top tier ones (like iPhoto does.) If any one knows this it would be really helpful for me as I will ensure I 'flatten' my keyword structure before installing Photos when it is released.