Bug 294260

Summary: Missing feature: implicit anchor (CSS anchor positioning)
Product: WebKit Reporter: Una <una.kravets>
Component: Layout and RenderingAssignee: Antti Koivisto <koivisto>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, fantasai.bugs, kiet.ho, koivisto, rik, simon.fraser, zalan
Priority: P2    
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 284226, 294066, 294112    
Bug Blocks: 291856    

Una
Reported 2025-06-10 07:55:11 PDT
Safari 26's implementation of anchor positioning is missing a key feature: [implicit anchoring](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_anchor_positioning/Using#implicit_anchor_association). This is critical DX for popovers and other commonly anchored UI elements. Implicit anchoring means users do not need to explicitly give each popover and invoking button an anchor name and position-anchor. Adding all of these additional styles muddles up HTML, and isn't reasonable to maintain in websites with many anchored elements. Please add this feature to Safari's implementation of anchor positioning to align with the [HTML specification](https://html.spec.whatwg.org/multipage/popover.html) and [CSSWG Draft](https://www.w3.org/TR/css-anchor-position-1/#implicit)!
Attachments
Anthony Ricaud
Comment 1 2025-06-10 09:59:09 PDT
@fantasai: I'm marking this as blocking css-anchor-position-1 since I agree with its importance. I'm not involved in the implementation so I'm just doing that to raise awareness.
Kiet Ho
Comment 2 2025-06-10 15:32:05 PDT
There have been work to implement this: * https://bugs.webkit.org/show_bug.cgi?id=284226 * https://bugs.webkit.org/show_bug.cgi?id=294112 * https://bugs.webkit.org/show_bug.cgi?id=294066 I can't comment when they'll be available in STP or Safari in iOS/macOS 26 though.
fantasai
Comment 3 2025-06-13 15:08:30 PDT
Fixed by Antti in the dependencies.
Una
Comment 4 2025-06-16 08:07:45 PDT
Awesome, thanks for your work on this :)
Note You need to log in before you can comment on or make changes to this bug.