Bug 225034 - Exclude creating a containing block for document root element (<html>) on will-change: filter/backdrop-filter
Summary: Exclude creating a containing block for document root element (<html>) on wil...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL: http://wpt.live/css/css-will-change/w...
Keywords: InRadar
: 243571 (view as bug list)
Depends on:
Blocks:
 
Reported: 2021-04-25 12:34 PDT by Tim Nguyen (:ntim)
Modified: 2022-08-13 08:09 PDT (History)
6 users (show)

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Description Tim Nguyen (:ntim) 2021-04-25 12:34:49 PDT 
will-change: filter/backdrop-filter should not create a containing block on the root element.

WPT: https://webkit-search.igalia.com/webkit/source/LayoutTests/imported/w3c/web-platform-tests/css/css-will-change/will-change-fixedpos-cb-003.html

Spec: https://drafts.fxtf.org/filter-effects/#FilterProperty

> A value other than none for the filter property results in the creation of a containing block for absolute and fixed positioned descendants unless the element it applies to is a document root element in the current browsing context. The list of functions are applied in the order provided.
Comment 1 Simon Fraser (smfr) 2021-04-26 09:25:39 PDT 
The root is always a containing block so I'm confused by this bug.
Comment 2 zalan 2021-04-26 09:39:49 PDT 
(In reply to Simon Fraser (smfr) from comment #1)
> The root is always a containing block so I'm confused by this bug.
I looked at the test case and apparently the root here means the <html> element and not the Initial Containing Block.
Please rename the bug.
Comment 3 Radar WebKit Bug Importer 2021-05-02 12:35:12 PDT 
<rdar://problem/77437740>
Comment 4 Sam Sneddon [:gsnedders] 2022-08-05 10:22:24 PDT 
*** Bug 243571 has been marked as a duplicate of this bug. ***