Their interface is a little confusing.
1. Imbox shows Subject line first and sender in the second line. (So when you are using other email services throughout a day, you are always confused, what is the sender and what is a subject line).
2. When you open an email, Sender comes in first-line and Now the subject is second. (just opposite to what they did in the first page of Imbox.
Choose any way, but keep the same view throughout the services.
Either they are confused or confusing us.