Bug 306598

Summary: REGRESSION: Scrolling during low frame rate (LFR) leads to unresponsive touch events on iOS 26
Product: WebKit Reporter: qfqf456456
Component: WebGLAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: djg, kbr, kkinnunen, sabouhallawa, simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari 26   
Hardware: iPhone / iPad   
OS: iOS 26   
Attachments:
Description Flags
Screen recording demonstrating touch unresponsiveness triggered by rapid vertical scrolling on iOS 26. none

qfqf456456
Reported 2026-01-29 22:37:27 PST
Created attachment 478199 [details] Screen recording demonstrating touch unresponsiveness triggered by rapid vertical scrolling on iOS 26. A critical issue has been identified on iOS 26 where frequent and rapid scrolling/swiping gestures lead to a complete loss of touch responsiveness. Once the issue is triggered, the page no longer responds to any scrolling or tapping events. URL: https://qfqf456456.github.io/qfqf456456-IOS26TouchDemo/ Steps to Reproduce: 1. Open the provided URL on a device running iOS 26. 2. Perform rapid and frequent swiping/scrolling gestures vertically on the page. 3. Continue the scrolling interaction for a few seconds. OS Version: iOS 26.2 Additional Context: This behavior is consistently reproducible on the provided demo page under high-frequency touch interaction.
Attachments
Screen recording demonstrating touch unresponsiveness triggered by rapid vertical scrolling on iOS 26. (2.24 MB, video/mp4)
2026-01-29 22:37 PST, qfqf456456 		no flags
Details
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Radar WebKit Bug Importer
Comment 1 2026-01-30 08:47:08 PST
<rdar://problem/169279665>
Simon Fraser (smfr)
Comment 2 2026-02-02 10:41:27 PST
I can reproduce poor scrolling on the testcase. The test page uses canvas to render, so it's not really scrolling.
Simon Fraser (smfr)
Comment 3 2026-02-02 10:44:49 PST
It's actually WebGL.
roberto_rodriguez2
Comment 4 2026-02-23 13:20:21 PST
Pull request: https://github.com/WebKit/WebKit/pull/59255
EWS
Comment 5 2026-02-25 15:04:29 PST
Committed 308237@main (a1a65ba028eb): <https://commits.webkit.org/308237@main> Reviewed commits have been landed. Closing PR #59255 and removing active labels.
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