Bug 191029

Summary:	[iOS 12] CSS Scroll Snap visual glitches on iOS when programmatically setting `style` on children
Product:	WebKit	Reporter:	t
Component:	CSS	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Major	CC:	jean.regisser, simon.fraser
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	iPhone / iPad
OS:	iOS 12

Description t 2018-10-29 07:25:28 PDT

Deriving from https://stackoverflow.com/questions/52989070/css-scroll-snap-visual-glitches-on-ios-when-programmatically-setting-style-on:

https://codepen.io/thomaslindstr_m/pen/qJLbwa
Pretty bare bones example above. I want to fade out the child I scrolled away from, but when CSS Scroll Snap is enabled, it starts glitching really bad on my iPhone iOS 12.0.1.

See video here: https://file-qacepzxlkb.now.sh
Before the reload I disabled Scroll Snap (JavaScript still running), after the reload, I enable it.

It runs perfectly fine in Safari 12.