Bug 300086

Summary: [scroll-snap] scrolling with scrollTo immediately bounces back on iOS
Product: WebKit Reporter: Callum Gare <callum>
Component: ScrollingAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari 26   
Hardware: iPhone / iPad   
OS: iOS 26   
Attachments:
Description Flags
Screen recording of using the reproduction case none

Callum Gare
Reported 2025-10-03 02:33:58 PDT
Created attachment 476947 [details] Screen recording of using the reproduction case In safari on iOS 26 scrolling with `window.scrollTo()` when scroll snap is on can result in the scroll position immediately rebounding back. This doesn't seem to happen to Safari 26 on macOS 15. I've created a reproducible case of this issue here: https://roaring-beignet-5140e4.netlify.app/ Clicking anywhere should attempt to scroll down to the bottom of the page. This usually works on first try after the page load but consistently fails after that. I've include a video of the issue in action:
Attachments
Screen recording of using the reproduction case (4.69 MB, video/mp4)
2025-10-03 02:33 PDT, Callum Gare 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Alexey Proskuryakov
Comment 1 2025-10-03 08:50:42 PDT
Thank you for the report. I think that the steps to reproduce are as below, please correct me if that's wrong. 1. Load https://roaring-beignet-5140e4.netlify.app/ , it starts with red. 2. Tap anywhere on the screen. It usually scrolls to cyan portion. 3. Scroll back to the top. 4. Tap again. Results: scrolls to cyan, but immediately bounces back to red. Expected results: scrolls to cyan, stays there. I can reproduce this on iOS 18.4.1.
Callum Gare
Comment 2 2025-10-03 17:25:25 PDT
Yep! That’s exactly right :) Interesting that it also occurs on iOS 18
Radar WebKit Bug Importer
Comment 3 2025-10-10 02:34:12 PDT
<rdar://problem/162354727>
Note You need to log in before you can comment on or make changes to this bug.