Thats because any full screen DirectX game will minimize if it loses focus. Lomac does this too

This took me a long time to find a fix for, but now TouchBuddy uses a NOACTIVATE flag on the window, which allows it to receive mouse move and clicks, but never actually becomes active. Due to that, the full screen game doesnt minimize. I was dancing a merry jig when I got this to work
TB can run locally (on second monitor attached to game machine) or in client/server (TB running in server mode wating for commands that are sent to it across the network from TB running in client mode on a separate PC).
The current release version still only uses normal windows "buttons", but the version in development support full skin mode, where you can have mutliple layers of images (supporting transparency/alpha channels) on multiple tabs. Have you seen the movie of it at work in Lomac? Its an early version of TB, and my graphics skills are lacking, so the buttons on the touchscreen are a bit basic, but the movie does show it at work quite nicely.
Movie Found Here (~50Mb DivX AVI)