ListView: `headerPositioning: ListView.OverlayHeader` suddenly disables mouse dragging / flicking

The title says it. headerPositioning: ListView.OverlayHeader disables flicking, although other values (or no value at all) has no effect — flicking ability even via mouse pointer is usually preserved.

Unlike what you might be thinking, footerPositioning doesn't affect a listview's scrolling abilities.

While my primary motivation was something quite unrelated, I looked up the source code of QQuickListView and found out that two of them — header and footer — sadly don't have a feature parity. Footer's positioning type is checked in much fewer places than header's one. This is also observable e.g. when using ListView.OverlayFooter: I don't see it being an overlay, or any different from a PullBack type.

Feel free to play with the attached project. It's a very minimal example built from scratch.