Took my first shot at trying to integrate MJ's polygon zone controls with my mock-up application, and I'm finding that the only practical approach is going to be subclassing MJ's class to add the handler which draws the pixmap in the background. I think as long as I draw the pixmap first, it should work OK, but I don't want to waste too much time on it, because it's not actually going to be the real approach we take to writing this bit of the app. Nevertheless I keep learning new stuff as I go.