> You can compose an instance of the sealed class in yours. But I can't subclass a sealed class to fix a bug or add a feature and pass it back into the framewo

> You can compose an instance of the sealed class in yours. But I can't subclass a sealed class to fix a bug or add a feature and pass it back into the framework to use. And yes, I have needed to do this otherwise I would never notice it was sealed in the first place.