Comment 3 for bug 1871499

well I asked GTK team in Oct '20 and indeed it does not exists.
https://discourse.gnome.org/t/how-to-sticky-first-column-of-gtktreeview-from-horizontal-scrolling/4601

I did also try what they suggested, which I though like you Jeff, but the problem is that the right part has a h-scrollbar at bottom while the left don't and so the lines never gets... aligned.
Still think of some way, but that's a pitty gtk has no sticky column :)