Bug 303137

Summary: [threaded-animations] document with a single `<div>` that has `opacity: 0` won't yield an accelerated scroll-driven animation
Product: WebKit Reporter: Antoine Quint <graouts>
Component: AnimationsAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: graouts, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=303136

Antoine Quint
Reported 2025-11-26 06:07:50 PST
The fix for bug 303136 has to work around an issue found in the existing test `webanimations/threaded-animations/scroll-timeline-in-iframe.html` where we would no longer accelerate the animation of a `<div>` that initially has `opacity: 0`.
Attachments
Radar WebKit Bug Importer
Comment 1 2025-11-26 06:10:19 PST
Antoine Quint
Comment 2 2026-02-13 09:35:40 PST
This is still current as of ToT on Feb 13, 2026. Need to get to the bottom of this.
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