Fighting for Top-Most Window in WinCE

[C# Programming]

We're having an issue with our project. Our software switches back and forth between a GPS software and our program. We have a button that we want to paint over the GPS software. The purpose of this button is to navigate back to our actual program from the GPS software. However, we're having some issues with painting and the two applications fighting for a top most position. When we try to give our button a top most position, it keeps having its LostFocus event called, which makes me believe that the two are indeed fighting for top position. Assuming this is true, what would be the best way to go about restricting the GPS window from having the top most position?

Thanks ahead of time.
-Brandon