If the recipients users don’t set custom avatar and the current_user send multiple messages with the same subject, it become very difficult to retrieve a specific conversation without the search bar, because all messages will be displayed with the exact same information. Since I don’t allow multiple recipients on my setup, it was not only confusing but irrelevant to display current username in the author column.
So I added the following code in function.php that force to always display recipient username instead of last message author name in messagebox.
This is only meant to be use with a max recipients of 1
Admin > Front End PM > Settings > Recipient > Max recipients : 1