Invisible scroll bars are a source of constant annoyance. And it sometimes takes me several attempts to move a window, because of all the various clickable things without visible boundaries. Frustrating.
gsettings set org.gnome.desktop.interface overlay-scrolling false
Of course, a smaller but no less surprising number of projects don't. The complexity of such a report is so low, though, that one might as well try for software that you actually use