RESOLVED FIXED310239
Fixed boxes anchored to children of sticky boxes should stick 
https://bugs.webkit.org/show_bug.cgi?id=310239
Summary Fixed boxes anchored to children of sticky boxes should stick
fantasai
Reported 2026-03-18 19:51:44 PDT
Testcase: https://knowler.dev/demos/Ats2b5t?codepen <div id="sticky">Sticky <div id="anchor">Anchor</div> <div id="anchored" popover="auto">Anchored</div> </div> <div id="content"></div> <script> anchored.showPopover(); </script> <style> #sticky { position: sticky; inset-block-start: 0; } #anchor { anchor-name: --anchor; } #anchored { position-anchor: --anchor; position-area: block-end span-inline-start; margin-block-start: 8px; } /* Presentation-only */ :root { color-scheme: dark; font-family: system-ui; background-image: linear-gradient(to bottom, RoyalBlue, MediumSeaGreen); } body { margin: 0; } #sticky { display: flex; justify-content: space-between; padding: 16px; background-color: DeepPink; font-weight: 600; } #content { block-size: 2000px; } </style>
Attachments
simplified testcase (744 bytes, text/html)
2026-03-26 09:45 PDT, fantasai 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Radar WebKit Bug Importer
Comment 1 2026-03-18 19:51:51 PDT
<rdar://problem/172884148>
fantasai
Comment 2 2026-03-26 09:45:07 PDT
Created attachment 478820 [details] simplified testcase
fantasai
Comment 3 2026-03-29 21:32:02 PDT
Pull request: https://github.com/WebKit/WebKit/pull/61656
EWS
Comment 4 2026-03-30 14:19:09 PDT
Committed 310255@main (344b0fc11db6): <https://commits.webkit.org/310255@main> Reviewed commits have been landed. Closing PR #61656 and removing active labels.
EWS
Comment 5 2026-03-31 01:19:42 PDT
Committed 305413.601@safari-7624-branch (f0f99c394805): <https://commits.webkit.org/305413.601@safari-7624-branch> Reviewed commits have been landed. Closing PR #4856 and removing active labels.
Note You need to log in before you can comment on or make changes to this bug.