It would be great if, when deleting subcollections, the contents of the subcollection would remain in the collection it subs. Or at least move the records to the trash where they can be retrieved. This has been a huge source of frustration for me because it is difficult to tell what is rooted in the collection as well as the subcollection. It seemed logical that putting an item into a subcollection would also put it into the collection, but this is not the case. The records simply vanish if you delete the subcollection without picking through every item and checking if it's in the collection, too.