I would like to be able to modify scrolling behavior in all applicable apps on my system via an installable app or extension. I am wondering where to start. It appears an action extension would be appropriate, but I could be overlooking something. I would also want to create some kind of pref pane or menu bar control panel to allow altering the default settings. If anyone can point me at a open source example of an action extension, then I would be able to study it as an example. Pros and cons of any suggested methods would be very much appreciated.