Bug 227705 - Missing or Flickering Elements
Summary: Missing or Flickering Elements
Status: RESOLVED DUPLICATE of bug 220892
Alias: None
Product: WebKit
Classification: Unclassified
Component: Compositing (show other bugs)
Version: Safari Technology Preview
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
Depends on:
Reported: 2021-07-06 08:24 PDT by Kerry
Modified: 2021-07-07 07:58 PDT (History)
2 users (show)

See Also:

Test case for flickering text (5.26 KB, text/html)
2021-07-06 08:24 PDT, Kerry
no flags Details
Test reduction (743 bytes, text/html)
2021-07-06 11:20 PDT, zalan
no flags Details
smfr testcase (1.11 KB, text/html)
2021-07-06 12:31 PDT, Simon Fraser (smfr)
no flags Details

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Description Kerry 2021-07-06 08:24:08 PDT
Created attachment 432933 [details]
Test case for flickering text

In the WordPress Block Editor, we were seeing elements flicker in Safari and the Safari Technology preview 127 in https://github.com/WordPress/gutenberg/issues/30803.

I've narrowed this down to a test case, which I've attached. It's also available at https://codepen.io/gwwar/pen/dyWYdmg

It should look like https://user-images.githubusercontent.com/1270189/124388676-c0a34f80-dc98-11eb-8987-aa0e6001c10c.mp4 with the bad behavior.

It's a little bit of a complex setup, requiring flex styles, an iframe, two fixed divs, and some z-index stacking contexts. We're are able to consistently reproduce this, so I do feel it's worthwhile to report. Let us know if folks have trouble reproducing or if y'all need more information. Thanks!
Comment 1 Kerry 2021-07-06 08:35:42 PDT
If it helps, there's also a few other videos available at https://github.com/WordPress/gutenberg/pull/32824#issuecomment-873280550 

Elements disappear or end up being ordered incorrectly when the iframe in .components-popover intersects with .block-editor-block-list__layout and causes a new compositing layer to be created.
Comment 2 zalan 2021-07-06 11:20:55 PDT
Created attachment 432947 [details]
Test reduction
Comment 3 Simon Fraser (smfr) 2021-07-06 12:31:53 PDT
Created attachment 432961 [details]
smfr testcase
Comment 4 Simon Fraser (smfr) 2021-07-06 14:39:42 PDT
Same as bug 220892, confirmed that the patch fixes it.

*** This bug has been marked as a duplicate of bug 220892 ***
Comment 5 Kerry 2021-07-07 07:58:26 PDT
Great to know this already had a patch fix! Thanks for looking into it.