Well, I've been fighting with an extremely simple Navigationsplitview for ages. Put a list in the sidebar, put 100 items in it, and render almost anything else in the detail on macos (one version back). Then select an item in the nav and hit the down arrow.

Depending on implementation, scrolling will get clipped to the visible area, it'll hold onto multiple selections if the first has been scrolled off screen, or the main thread will get thrashed and performance will be about what the current settings menu is.

I haven't found something that I don't have to accept a really mediocre experience with, but next I'm going to try rewriting it with NSTable