By default all lists in the BetterMail interface are ordered chronologically with the newest item displayed on the top of lists, including drop down lists. This allows users to quickly find recent data.
You now have the option to order lists alphabetically. This option makes finding data easier if your account uses a lot of code-names – or if you simply prefer your lists ordered alphabetically.
To change the order preference for your user account go to the My Account / My Preferences page.