Bug 190500

Summary: Bad behavior of scrolling, position:fixed inside flattened iframe
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED CONFIGURATION CHANGED    
Severity: Normal CC: ajuma, bfulgham, fred.wang, koivisto, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 196290    
Bug Blocks:    
Attachments:
Description Flags
Testcase none

Description Simon Fraser (smfr) 2018-10-11 17:11:21 PDT
Created attachment 352107 [details]
Testcase

Attached test case, when loaded on iOS, shows bad problems where the position of the logging box jumps around, and the content doesn't get fully tilted, and it can't be scrolled.
Comment 1 Radar WebKit Bug Importer 2018-10-11 17:11:47 PDT
<rdar://problem/45211964>
Comment 2 Simon Fraser (smfr) 2019-03-15 21:48:44 PDT
Even with frame flattening off, I see two issues with this test content on iPad:
1. On first load, the position:fixed in the iframe is missing
2. After scrolling the iframe for a bit, we lose all the tiles in the logging element.

My guess is that GraphicsLayer geometry isn't getting updated somehow, triggering incorrect visible rects. Maybe this is related to boundsOrigin vs. position differences.
Comment 3 Frédéric Wang (:fredw) 2019-03-21 05:00:40 PDT
@smfr: Not sure how it relates to bug 194433, but AFAIK my remaining tests for position: fixed/sticky when async frame scrolling is enabled still don't pass.
Comment 4 Simon Fraser (smfr) 2019-03-27 10:26:55 PDT
https://trac.webkit.org/changeset/243539/webkit fixes position:fixed inside the iframe. I still see missing tiles in the scroller sometimes.
Comment 5 Antti Koivisto 2019-05-23 15:21:08 PDT
Appears to be fixed.