Bug 301616

Summary: Overconstrained sticky positioned element shifts on scroll
Product: WebKit Reporter: Johannes Odland <johannes.odland>
Component: ScrollingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
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 the issue none

Johannes Odland
Reported 2025-10-29 01:30:50 PDT
Created attachment 477220 [details] Screen recording of the issue When a sticky element is larger than the sticky view rectangle, the _end_ edge of the sticky view rectangle should be adjusted to accommodate the sticky element. As a result, the top edge should align as specified. In iOS Safari however, the sticky element is sometimes shifted around when scrolling, so that the top edge no longer aligns. Minimal reproduction: https://johannesodland.github.io/browserbugs/2025/safari-shifting-of-overconstrained-sticky.html When scrolling in the above example, the last sticky element with a purple outline is sometimes shifted around, revealing another sticky element with a red outline.
Attachments
Screen recording of the issue (15.48 MB, video/quicktime)
2025-10-29 01:30 PDT, Johannes Odland
no flags
Radar WebKit Bug Importer
Comment 1 2025-10-29 10:40:12 PDT
Johannes Odland
Comment 2 2025-11-23 01:34:28 PST
EWS
Comment 3 2025-12-11 20:21:01 PST
Committed 304335@main (89d5b99990f0): <https://commits.webkit.org/304335@main> Reviewed commits have been landed. Closing PR #54384 and removing active labels.
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