How to Exit AirDroid

The software does not seem to have an exit or quit option and once I've done what I need it would be good to exit and save resources and battery. Plus my Android keeps yelling at me that AirDroid has been running for XX minutes, do I want to shut it down?

Droid Bionic
Android 2.3.4

Using the back button with the app in full view on the main screen will ask you "Exit AirDroid?" and give you the option yes or no.

Thank you! That's very handy and totally non-intuitive.
(AirDroid devs -- your UI is great with this lone exception! Even a menu item would be better than expecting users think the back button is also an exit button.)