My "all inboxes" view disappeared. I was on mailboxes, swiped left and the all inboxes setting was gone. The remaining views include today, unread, attachments, to/cc/bcc/ all drafts and all sent. The result is that I have to go into each specific email account to see all messages that I've read. It doesn't appear to be an IOS 8 bug because I had all inboxes after I updated to IOS 8.0. I just don't know where all inboxes went or how to get it back.