jittering

[croutor]

HW: Chuwi hi 10

when my finger remains on the screen I can see that pointer is jittering.
This cause some long web pages to jitter when I press the scrollbar for example and maintain my finger on it.

To solve this I've added a hysteresis parameter. See attached patch (renamed to txt).

hysteresis_param.txt

This may need some rework.

Thanks for your work.