gtk_text_view_scroll_to_mark() does not respect within_margin
If scrolling to a position which is already on screen, and within_margin is set to .25, you'd expect it to not fully center the line on screen (and do minimal movement). The behavior in GTK 4 seems to be a bit different from GTK 3 in that within_margin
seems to be ignored.
Seeing this in gnome-text-editor#168 (closed)