Bug 301616

Summary:

Overconstrained sticky positioned element shifts on scroll

Product:

WebKit

Reporter:

Johannes Odland <johannes.odland>

Component:

Scrolling

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

simon.fraser, webkit-bug-importer

Priority:

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	Details
View All Add attachment proposed patch, testcase, etc.

Radar WebKit Bug Importer

Comment 1 2025-10-29 10:40:12 PDT

<rdar://problem/163654023>

Johannes Odland

Comment 2 2025-11-23 01:34:28 PST

Pull request: https://github.com/WebKit/WebKit/pull/54384

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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