Native scroll
Mouse drag, native touch
pointerMode: 'mouse', scrollMode: 'native' on a viewport with overflow: auto.
The mouse drags with inertia, touch, scrollbars and the sticky header inside are the browser's own.
The panel follows any scroll, including the scrollbar.
Drag the whole page
viewport: document.documentElement, content: document.body, vertical, mouse only.
Turn it on and drag the page anywhere outside the scroller above.