Whats up with Attachments?

Does the same as most inboxes these days. Snooze, archive with swipes which is a simple but great feature. And the ability to use google hangouts right in the same application is awesome.

But attaching docs from your desktop cant be done. I drag them but nothing happens, I select the paperclip to attach items, but you can only select from a few things on your google drive and recent items mailed to you. Its baffling...

Sunriser! about Inbox for Gmail