I still find it hard to believe that if you plug a mouse to your macbook, you can have scroll working as expected either on a mouse or on a trackpad, but not both. They even made two settings, but then decided that one should silently alter the other to match, without notifying or even listening to the user.
I guess in Apple’s mind people who plug in USB mouse immediately stop using trackpad for anything for the rest of their life. I can’t find another explanation for this nonsense.