Bug 225467

Summary:

REGRESSION (Safari 14): Submenus on https://codelearn.cat don't show

Product:

WebKit

Reporter:

Simon Fraser (smfr) <simon.fraser>

Component:

Layout and Rendering

Assignee:

Simon Fraser (smfr) <simon.fraser>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

bfulgham, changseok, esprehn+autocc, ews-watchlist, glenn, kondapallykalyan, ntim, pdr, simon.fraser, webkit-bug-importer, zalan, zimmermann

Priority:

Keywords:

InRadar

Version:

Safari Technology Preview

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Patch	none

Description Simon Fraser (smfr) 2021-05-06 09:59:29 PDT

Hover the menus on https://codelearn.cat: hover "Centres" then "Barcelona" and the hover menus fail to appear.

To reproduce, your window needs to be short enough for the longer menus to scroll.

Comment 1 Radar WebKit Bug Importer 2021-05-06 10:00:21 PDT

<rdar://problem/77612276>

Comment 2 Simon Fraser (smfr) 2021-05-06 10:00:32 PDT

Probably related to async overflow scroll and compositing.

Comment 3 Simon Fraser (smfr) 2021-06-08 14:20:37 PDT

This might be fallout from the RenderLayer/ScrollableArea split.

There's a composited layer with overflow:scroll, and overflow is being toggled to 'visible'. We fail to remove the compositing clipping layer, so the content remains clipped.

This is happening because RenderBox::requiresLayerWithScrollableArea() is called from RenderLayer::styleChanged() (i.e. before layout) but it consults hasHorizontalOverflow() || hasVerticalOverflow() which depend on layout.

Comment 4 Simon Fraser (smfr) 2021-06-08 14:21:03 PDT

We also never remove the RenderLayerScrollableArea and it seems like we should.

Comment 5 Simon Fraser (smfr) 2021-06-09 10:55:29 PDT

Created attachment 430979 [details]
Patch

Comment 6 EWS 2021-06-22 11:33:32 PDT

Committed r279130 (239044@main): <https://commits.webkit.org/239044@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 430979 [details].