Bug 235904

Summary:	`scroll-snap-type: x mandatory` jittery
Product:	WebKit	Reporter:	Bramus <bramus>
Component:	Scrolling	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	bfulgham, mrobinson, simon.fraser, webkit-bug-importer, zalan
Priority:	P2	Keywords:	InRadar
Version:	Safari Technology Preview
Hardware:	Unspecified
OS:	macOS 12

Description Bramus 2022-01-31 11:23:51 PST

When checking out the MDN demos on https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-snap-type with `scroll-snap-type: x mandatory` selected, it acts a bit jittery when slowish-ly scrolling over the scroll container and then releasing. Just before it snaps, you can see it jump back a little bit.

See recording at https://www.youtube.com/watch?v=vLapfq0flMM

You can see it really good at the 4 second, where scrolling back from box 3 to box 2. It jumps a little bit back, before snapping.

Comment 1 Simon Fraser (smfr) 2022-02-02 10:05:12 PST

What Safari are you seeing this with? STP 139?

Comment 2 Bramus 2022-02-02 10:33:07 PST

Seeing this behavior in both of these versions (on macOS 12.1 (21C52)):

- Stable: Version 15.2 (17612.3.6.1.6)
- STP: Release 139 (Safari 15.4, WebKit 17613.1.14.41.2)

Comment 3 Bramus 2022-02-02 11:23:29 PST

Updated my machine and Safari TP.

Seeing the same behavior on the latest macOS 12.2 (21D49) using STP Release 139 (Safari 15.4, WebKit 17613.1.14.41.3)

Comment 4 Radar WebKit Bug Importer 2022-02-07 11:24:19 PST

<rdar://problem/88584478>