When using RMAIL, speedbar will display two sections. The first is a layer one reply button. Clicking here will initialize a reply buffer showing only this email address in the ‘To:’ field.
The second section lists all RMAIL folders in the same directory as your main RMAIL folder. The general rule is that RMAIL folders always appear in all caps, or numbers. It is possible to save mail in folders with lower case letters, but there is no clean way of detecting such RMAIL folders without opening them all.
Each folder can be visited by clicking the name. You can move mail from the current RMAIL folder into a different folder by clicking the ‘<M>’ button. The ‘M’ stands for Move.
In this way you can manage your existing RMAIL folders fairly easily using the mouse.