Mail no longer opens to page with all my mailboxes

I have iPhone 5c with iOS 9.1. Since the upgrade to 9.1, I have been having small but irritating email issue.

Previously, when I tapped the Mail icon to open up the Mail app, it would go to the page with all of my Mailboxes. (I have several email accounts on this phone.)

But now, when I open the Mail app, it goes straight to the Inbox of whichever mail account I set as primary. If I want to get to the other mailboxes I have to tap the back arrow. If I change my primary email account, the next time I open the Mail app it will go to that account's Inbox.

I need the app to open to the page with all my Mailboxes so I can see right away which ones have new mail.

What can I do to restore the app so it doesn't assume I want to see my default email account first? Is there a setting I need to change?

Zane B Stein