Better control of the fast scrolling handle

[gituser1000000]

After grabbing the handle on right side for fast scrolling, all it takes is a little straying to the left and the handle would slip. In my opinion, this makes the gesture a bit fragile as we have to be careful trying to keep the motion as straight up and down as possible.

Maybe we could improve the experience by ignoring the finger's horizontal movement after the handle has been grabbed.