TIL about ruler-mode; now I can delete my own half-assed implementation of the same.

And compare-windows looks really handy. I was about to write a note in my init file to my future self telling me to start using that, but then I saw there is already a note there from my past self, telling me about compare-windows.

scroll-all-mode seems useful, but it seems to only handle keyboard scrolling, not mouse-wheel?