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65259
Safari flashes scrollbar for overflow:auto/scrollbar elements that are hidden behind other elements
https://bugs.webkit.org/show_bug.cgi?id=65259
Summary
Safari flashes scrollbar for overflow:auto/scrollbar elements that are hidden...
Bart S.
Reported
2011-07-27 08:24:58 PDT
I'm working on a lightbox and have been noticing a strange scrollbar flashing on the page every time I give that tab focus. I just realized this was because there is an element behind it that has overflow:auto. WebKit should respect the z-index of elements for the scrollbar and flash it at the appropriate level (in this case behind my lightbox).
Attachments
Test case (HTML file) for flashing scrollbar for overflow:auto elements under other elements with higher z-index.
(3.04 KB, text/html)
2011-07-27 12:02 PDT
,
Bart S.
no flags
Details
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Add attachment
proposed patch, testcase, etc.
Alexey Proskuryakov
Comment 1
2011-07-27 10:31:42 PDT
Do you have a test case that you could attach to the bug?
Bart S.
Comment 2
2011-07-27 12:02:08 PDT
Created
attachment 102162
[details]
Test case (HTML file) for flashing scrollbar for overflow:auto elements under other elements with higher z-index.
Alexey Proskuryakov
Comment 3
2011-08-19 13:16:39 PDT
Thank you for the great test case.
Beth Dakin
Comment 4
2011-08-19 13:27:50 PDT
Indeed, right now overlay scrollbars paint on top of everything. It is extraordinarily difficult to get them to paint in the right layer, which is why we took the shortcut for now.
jonjohnjohnson
Comment 5
2018-12-10 07:59:38 PST
bdakin@apple.com
Any changes/thoughts on this in the last seven years? It seems the initial flashing isn't exactly the/an issue anymore, though the test case submitted from a duplicate filing simply shows that scrollbars still painting above content that it shouldn't be.
https://bug-96825-attachments.webkit.org/attachment.cgi?id=164226
I'm on 10.12.6 with safari 12.0.2 in the test case when scrolling the red container, it's scrollbar shows above the green element which is "stacked" above the red container. I'm guessing the shortcut that was taken is something that is bypassed on iOS with the use of `-webkit-overflow-scrolling: touch` compositing in a different way than desktop??? From what I've seen blink has remedied this issue for mac. And gecko *only has this issue on mac *if stacking context places content above with use of implicit/initial `z-index` value of `auto`, but works well when explicitly setting `z-index`.
Ahmad Saleem
Comment 6
2023-06-15 12:24:29 PDT
I am not able to reproduce using Safari 16.5, where the scrollbar of red container overlap on top of green container as per
Comment 05
test case and also don't see any scrollbar flashing in
Comment 03
. NOTE - I do have 'scrollbars' to be always visible option turned on. Is it fixed or requires to turn off above setting?
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