Bug 190500 - Bad behavior of scrolling, position:fixed inside flattened iframe
Summary: Bad behavior of scrolling, position:fixed inside flattened iframe
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
Keywords: InRadar
Depends on: 196290
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Reported: 2018-10-11 17:11 PDT by Simon Fraser (smfr)
Modified: 2019-05-23 15:21 PDT (History)
7 users (show)

See Also:

Testcase (2.07 KB, application/zip)
2018-10-11 17:11 PDT, Simon Fraser (smfr)
no flags Details

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

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
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.