RESOLVED DUPLICATE of bug 261662262926
Webkit `backdrop-filter` does not establish a containing block 
https://bugs.webkit.org/show_bug.cgi?id=262926
Summary Webkit `backdrop-filter` does not establish a containing block
Josh
Reported 2023-10-09 14:53:14 PDT
Created attachment 468129 [details] Testing HTML document Webkit does not create a stacking context when `backdrop-filter` is applied.
Attachments
Testing HTML document (4.64 KB, text/html)
2023-10-09 14:53 PDT, Josh 		no flags
Details
PNG of Webkit fail :( (197.86 KB, image/png)
2023-10-09 14:54 PDT, Josh 		no flags
Details
PNG of chromium pass :) (91.56 KB, image/png)
2023-10-09 14:55 PDT, Josh 		no flags
Details
PNG of Gecko pass :) (203.62 KB, image/png)
2023-10-09 14:56 PDT, Josh 		no flags
Details
WebKit ToT Screenshot - Passing (373.59 KB, image/png)
2023-10-09 17:16 PDT, Ahmad Saleem 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Josh
Comment 1 2023-10-09 14:54:42 PDT
Created attachment 468130 [details] PNG of Webkit fail :(
Josh
Comment 2 2023-10-09 14:55:27 PDT
Created attachment 468131 [details] PNG of chromium pass :)
Josh
Comment 3 2023-10-09 14:56:29 PDT
Created attachment 468132 [details] PNG of Gecko pass :)
Ahmad Saleem
Comment 4 2023-10-09 17:13:54 PDT
Failing on WebKit ToT (269084@main) as well.
Ahmad Saleem
Comment 5 2023-10-09 17:14:55 PDT
(In reply to Ahmad Saleem from comment #4) > Failing on WebKit ToT (269084@main) as well. Ignore - passing on WebKit ToT.
Ahmad Saleem
Comment 6 2023-10-09 17:16:06 PDT
Created attachment 468139 [details] WebKit ToT Screenshot - Passing Reference screenshot from WebKit ToT - passing and matching other browsers. NOTE - Minibrowser show 'Safari 16'.
Ahmad Saleem
Comment 7 2023-10-09 17:17:18 PDT
Marking this as 'RESOLVED CONFIGURATION CHANGED', please triage and add related commit but this is passing on WebKit upstream and might in future Safari Technology Preview releases.
Oriol Brufau
Comment 8 2025-02-11 04:28:04 PST
This is mixing up concepts, your testcase doesn't check whether the element establishes a stacking context, but whether it establishes a containing block for abspos descendants. I don't have an old build to confirm, but looking at the code it seems clear that `backdrop-filter` established a stacking context from the very first implementation: https://github.com/WebKit/WebKit/commit/4b6363d3d2519ca9f72750e42b06a4e9f962adbf#diff-7cc093e2dd898772c51e0313408a4e9441d4d62049786b0dcac3089a226ef995R125 So this is a duplicate of bug 261662. *** This bug has been marked as a duplicate of bug 261662 ***
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