Sync selected heading in Outline with document scroll position

Yes, I see two possible implementations of this, one that reacts on click and one that reacts on scroll, possibly after a short delay (this is what Quiet Outline plugin does).

The feature was requested in this (archived) thread, and the last post says it was implemented in v1.8.1 but doesn’t indicate whether an option needs to be checked and no more information (and it’s archived so I can’t ask).
https://forum.obsidian.md/t/outline-snap-to-location-in-note-auto-scroll/76991/16

Oddly enough, in my main vault and only there, a barebone auto-scroll feature is actually working on click. It has limitations though: if the parent heading is folded, it’s unable to expand it and auto-scroll to the sub-heading where you clicked.

I couldn’t reproduce this in Sandbox so I can’t even open a bug report about this: I first need to make this basic feature work in Sandbox!

Unfortunately I was unable to tell which plugin or option magically enabled this in my vault. I disabled all my plugins and yet the behavior was still there (maybe I’ll restart Obsidian next time, or try changing more setting flags). I just know that it exists somewhere (and I’m talking about the native Outline, not Quiet Outline which of course does the job).