Hoping this has not been suggested and denied already: did my best googling.
I think it would be nice to be able to go from the current handled private message, to the one immediately above it (more recent one). I believe this is similar to a function available in outlook mail.
Suggested placement of the new button:
Direction which you would move when clicking it.
The function could be made to only appear when there's a new message with the state: unread - or for all messages.
Perhaps you guys think this is unneccessary, as it would all only save you from loading one page and a click. Personally I appreciate any avoided page-loading and would find it convenient
Vote and leave input if have any!
thanks.