For next push please rebase upon master branch or rc5.
Tested aecfceed3baa21e5bb152bf9ecedd322a5549581. The kinetic momentum feels good in isolation but it introduces new problem in combination.
* Fling the two-finger scroll quickly down and let go. * Before the downward momentum ends two-finger again to scroll up. * The intended upward scroll direction doesn't happen. It actually continues scrolling down.
* Sometimes a different problem happens. Fling the scroll up or down then immediately move the mouse with a single finger. It sometimes goes haywire.
Would canceling the momentum immediately upon any other touch fix this? There might be good reasons why previous Linux input didn't implement momentum?