Bug 63331

Summary: [Async overflow scrolling] Incorrect clipping of fixed element inside overflow element with compositing
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: abucur, dino, fujii.hironori, koivisto, simon.fraser, tonikitoo, vangelis, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=242673
Attachments:
Description Flags
Testcase
none
Another testcase none

Simon Fraser (smfr)
Reported 2011-06-24 10:19:35 PDT
Created attachment 98505 [details] Testcase Testcase shows incorrect clipping of fixed element inside overflow:scroll element when compositing is enabled. The fixed element should not be clipped.
Attachments
Testcase (1.29 KB, text/html)
2011-06-24 10:19 PDT, Simon Fraser (smfr) 		no flags
Details
Another testcase (705 bytes, text/html)
2012-04-20 11:57 PDT, Dean Jackson 		no flags
Details
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Simon Fraser (smfr)
Comment 1 2011-06-24 10:59:18 PDT
The assumption that if an element with z-index has overflow, all its children are clipped by that overflow is false for fixed position elements.
Simon Fraser (smfr)
Comment 2 2011-09-02 10:40:55 PDT
This is tricky. Overflow get special treatment for positioned elements. I'm going to have to put them outside the clipping layer, and give each their own clipping layer or something.
Dean Jackson
Comment 3 2012-04-20 11:57:11 PDT
Created attachment 138136 [details] Another testcase
Dean Jackson
Comment 4 2012-04-20 11:58:29 PDT
*** Bug 83190 has been marked as a duplicate of this bug. ***
Simon Fraser (smfr)
Comment 5 2013-04-29 14:48:59 PDT
*** Bug 115377 has been marked as a duplicate of this bug. ***
Radar WebKit Bug Importer
Comment 6 2013-04-29 14:51:36 PDT
<rdar://problem/13766693>
Simon Fraser (smfr)
Comment 7 2020-04-09 15:03:32 PDT
*** Bug 196145 has been marked as a duplicate of this bug. ***
Fujii Hironori
Comment 8 2022-07-14 19:16:24 PDT
Comment on attachment 138136 [details] Another testcase The latest Safari has no problem for this test case. It seems another problem already fixed.
Fujii Hironori
Comment 9 2022-07-14 19:18:00 PDT
STP 148 still has this issue. Disabling Async Overflow Scrolling Internal Feature setting of MiniBrowser can work around the issue.
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