This is the reading pane in the new conversation mode with several messages in the conversation. The buttons are on the View tab but you can add them to the Home ribbon or the Quick Access Toolbar (QAT) to make it easier.
Switching back and forth between Classic and Conversational mode is a simple click of the button. Even so, it takes some getting used to and I'm not sold on it (change is hard, even for me!), especially with messages with long signatures as I think it makes it harder to follow the message. This new format should have a familiar feel to anyone who uses forums.
