Subject: bug#28342: 26.0.50; (OSX) Jumpy Scrolling using Trackpad

From: [email-masked] (Charles A. Roelli)
Date: Tue, 05 Sep 2017 22:14:08 +0200

> Resent-From: James Nguyen <[email-masked]>
> Original-Sender: "Debbugs-submit" <[email-masked]>
> Resent-CC: [email-masked]
> Resent-Sender: [email-masked]
> From: James Nguyen <[email-masked]>
> Date: Sun, 03 Sep 2017 17:22:29 -0700
> Content-Type: text/plain
> 
> 
> Recipe:
> 
> emacs -Q
> 
> (setq scroll-margin 5
>       scroll-step 1
>       scroll-conservatively 10000
>       scroll-preserve-screen-position 1
> 	  mouse-wheel-scroll-amount '(1)
> 	  mouse-wheel-progressive-speed nil
> 	  mouse-wheel-follow-mouse 't)
> 
> Open another buffer (init.el for example). Use only one window.
> Scroll with trackpad up and down.
> Use trackpad mouse to click past the scroll margin.
> Try scrolling up and down with trackpad. It will jump wildly.

What jumps wildly?  Does removing any of these settings stop the issue
from occurring?