Sure but that's not any different if your application depended on some other GNOME or KDE specific API. If KDE decides an API is KDE only and GNOME doesn't want to make their own implementation then there's not much that you could ever do about that. The point with using a toolkit is that it's an abstraction layer that handles the differences between window systems and implementations for you. It would be better if you mentioned the specific reason why your app is breaking because that would likely be a bug in the toolkit.