This app is incredibly useful, and works superbly. One suggestion to the developer- maybe make the backgrounds of the different screens (styles and colors, settings and stacks, etc) the same color. The green and blue backgrounds are sort of ugly. Also, is it really necessary to make the user input their username and password with every change? Perhaps you could have an "unlock" action similar to what is found in the system prefs, so the usrname and pass would only have to be entered once.

Aside from those minor qualms, I highly recommend this application.