BTW

All frameworks have many classes combined in an apparently arbitrary way into class libraries. I once wanted to create a DLL. I used a particular class from a particular library. What happended was the DLL became enormous. The particular class was a subclass of another class in another class library. That class library was brought into the project and all kinds of files that supported the classes in that library.

The moral of the story is keep things as granular as possible to avoid the unexpected. Compilers are no smart enough to learn from their mistakes, but we are.