Bug 296803

Summary:

Container style queries are either not applied or canceled (e.g., on user interactions) on custom elements in shadow DOM of other custom elements

Product:

WebKit

Reporter:

Dmitry Sharabin <dmitrysharabin>

Component:

CSS

Assignee:

Nobody <webkit-unassigned>

Status:

NEW

Severity:

Normal

CC:

karlcow, koivisto, webkit-bug-importer, woodlxf00

Priority:

Keywords:

BrowserCompat, InRadar

Version:

Safari 18

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Screenshot of the testcase state before user interaction	none
Screenshot of the testcase state after user interaction	none
rendering in safari, firefox, chrome	none

Dmitry Sharabin

Reported 2025-08-01 05:23:12 PDT

Created attachment 476248 [details] Screenshot of the testcase state before user interaction See this reduced testcase on Codepen: https://codepen.io/dmitrysharabin/pen/ByoWawb The bug can also be observed in Safari Technology Preview Release 224 (WebKit 20622.1.20.1)

Attachments
Screenshot of the testcase state before user interaction (61.79 KB, image/png) 2025-08-01 05:23 PDT, Dmitry Sharabin	no flags	Details
Screenshot of the testcase state after user interaction (60.34 KB, image/png) 2025-08-01 05:24 PDT, Dmitry Sharabin	no flags	Details
rendering in safari, firefox, chrome (291.05 KB, image/png) 2025-08-04 21:30 PDT, Karl Dubost	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Dmitry Sharabin

Comment 1 2025-08-01 05:24:39 PDT

Created attachment 476249 [details] Screenshot of the testcase state after user interaction

Karl Dubost

Comment 2 2025-08-04 21:30:16 PDT

Created attachment 476282 [details] rendering in safari, firefox, chrome * This is passing only in Chrome. * Firefox has both red * Safari has red on the first one after interaction.

Karl Dubost

Comment 3 2025-08-04 21:31:11 PDT

Tested on Safari Technology Preview 26.0 (224) 20622.1.20.1 Firefox Nightly 143.0a1 14325.7.28 Google Chrome Canary 140.0.7331.0 7331.0

Radar WebKit Bug Importer

Comment 4 2025-08-08 05:24:14 PDT

<rdar://problem/157838763>

Woody Lee

Comment 5 2025-10-14 22:48:20 PDT

Tested on Mac OS Safari 26, and it works well. But reproduces on IOS Safari 26.

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