Bug 308295

Summary: Do not apply style containment to elements without a principal box
Product: WebKit Reporter: shimaryuhei
Component: CSSAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: koivisto, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   

shimaryuhei
Reported 2026-02-20 05:53:04 PST
Style containment should have no effect on elements that do not generate
Attachments
Add attachment proposed patch, testcase, etc.
shimaryuhei
Comment 1 2026-02-20 05:54:02 PST
Style containment should have no effect on elements that do not generate a principal box, per the CSS Containment specification. WebKit currently applies `contain: style` to such elements. This change makes the behavior spec-compliant. Spec: https://drafts.csswg.org/css-contain/#containment-style WPT: https://wpt.live/css/css-contain/contain-style-counters-002.html
shimaryuhei
Comment 2 2026-02-20 05:56:09 PST
Pull request: https://github.com/WebKit/WebKit/pull/59084
Radar WebKit Bug Importer
Comment 3 2026-02-27 05:53:11 PST
<rdar://problem/171352369>
EWS
Comment 4 2026-02-27 08:39:05 PST
Committed 308341@main (37e919fcc616): <https://commits.webkit.org/308341@main> Reviewed commits have been landed. Closing PR #59084 and removing active labels.
Note You need to log in before you can comment on or make changes to this bug.