bug#65070:

[Eli Zaretskii]

> Date: Tue, 08 Aug 2023 10:19:39 +0000
> From: max@mal-richtig.de
> TLS-Required: No
> 
> I think I have the same problem.
> 
> After the update to Emacs 29.1 (on Windows), I can only scroll upwards 
> somehow with the touchpad.
> Scolling is also kind of "jumpy" as it is not scrolling upwards smothly but 
> jumps up a couple of lines at a time.
> However, when using the mouse instead of the touchpad, scrolling works fine 
> and is smooth.
> 
> < C-h l > shows correct movement, so emacs somehow "understands" the 
> touch-gestures but does not execute them right.
> 
>  <wheel-up>                                     ;; mwheel-scroll
>  <double-wheel-up>                              ;; mwheel-scroll
>  <triple-wheel-up>                              ;; mwheel-scroll
>  <triple-wheel-up>                              ;; mwheel-scroll
>  <triple-wheel-up>                              ;; mwheel-scroll
>  <wheel-down>                                   ;; mwheel-scroll
>  <double-wheel-down>                            ;; mwheel-scroll
>  <triple-wheel-down>                            ;; mwheel-scroll
>  <triple-wheel-down>                            ;; mwheel-scroll
>  C-h l                                          ;; view-lossage
> 
> This (or similar events) show equally in the log for both touchpad and/or 
> mouse.
> Tripple-wheel is shown when scrolling fast.
> 
> I can reproduce this scrolling-issue with `emacs -Q` - so I don't think it is 
> a configuration issue.

Po Lu, could you perhaps look into this?  Or at least tell me which
w32 code is activated when the user scrolls via the touchpad on
MS-Windows, and then I will try to take a look.

Thanks.