Maintaining a menu gathered across all the open documents could be tricky. Here’s a simple solution using UserDefaults and NotificationCenter.
Where to find hidden global default settings, and how to change them without paying for a utility like MacPilot.
How much more difficult is it to write your own code to handle user preferences, rather than letting UserDefaults handle them?
Developers should consider letting users export and import suites of settings, to determine an app’s persona, or flavours of working environment.
The current macOS implementation of preferences is appalling design in every respect, and is essentially undocumented even for developers. Is this the way that macOS is heading?