Bug 313161

Summary:

"scrollbar-gutter" on root element is misplaced in RTL layouts

Product:

WebKit

Reporter:

oss

Component:

Layout and Rendering

Assignee:

alan <zalan>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

bfulgham, simon.fraser, webkit-bug-importer, zalan

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Mac (Apple Silicon)

OS:

macOS 26

Attachments:

Description	Flags
Example of RTL gutter placement on root element, root element inside iframe and normal elements	none
Patch	none
[fast- cq]Patch	none
[fast-cq]Patch	none

oss

Reported 2026-04-23 12:44:04 PDT

Created attachment 479273 [details] Example of RTL gutter placement on root element, root element inside iframe and normal elements In scroll containers, Webkit renders scrollbars left-sided in RTL layouts, both for normal elements as well as root elements. Unfortunately it places the corresponding scrollbar-gutter, right-sided for root elements, for both top window and nested documents. This causes layout to shift when going the gutter is replaced by the actual scrollbars, whereas the gutter should always be in-place.

Attachments
Example of RTL gutter placement on root element, root element inside iframe and normal elements (2.78 KB, text/html) 2026-04-23 12:44 PDT, oss	no flags	Details
Patch (4.03 KB, patch) 2026-04-29 16:03 PDT, alan	no flags	Details Formatted Diff Diff
[fast- cq]Patch (3.92 KB, patch) 2026-04-29 17:07 PDT, alan	no flags	Details Formatted Diff Diff
[fast-cq]Patch (3.92 KB, patch) 2026-04-30 04:34 PDT, alan	no flags	Details Formatted Diff Diff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.

alan

Comment 1 2026-04-29 16:03:57 PDT

Created attachment 479383 [details] Patch

Simon Fraser (smfr)

Comment 2 2026-04-29 16:45:41 PDT

Comment on attachment 479383 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=479383&action=review > Source/WebCore/page/LocalFrameView.cpp:7285 > + if (scrollbarGutterStyle().isStableBothEdges() || shouldPlaceVerticalScrollbarOnLeft()) I'm not sure this is right; doesn't it leave a gap on the left even when scrollbars are overlay (no gutter)? > LayoutTests/fast/scrolling/scrollbar-gutter-stable-rtl-viewport-expected.html:1 > +<!DOCTYPE html>  Mock scrollbars should be OK here.

Simon Fraser (smfr)

Comment 3 2026-04-29 16:45:58 PDT

View in context: https://bugs.webkit.org/attachment.cgi?id=479383&action=review > Source/WebCore/page/LocalFrameView.cpp:7285 > + if (scrollbarGutterStyle().isStableBothEdges() || shouldPlaceVerticalScrollbarOnLeft()) I'm not sure this is right; doesn't it leave a gap on the left even when scrollbars are overlay (no gutter)? > LayoutTests/fast/scrolling/scrollbar-gutter-stable-rtl-viewport-expected.html:1 > +<!DOCTYPE html>  Mock scrollbars should be OK here.

alan

Comment 4 2026-04-29 17:07:26 PDT

Created attachment 479384 [details] [fast- cq]Patch

EWS

Comment 5 2026-04-30 04:29:26 PDT

Patch 479384 does not build

alan

Comment 6 2026-04-30 04:34:32 PDT

Created attachment 479390 [details] [fast-cq]Patch

EWS

Comment 7 2026-04-30 06:31:22 PDT

Committed 312360@main (92693c2591b2): <https://commits.webkit.org/312360@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 479390 [details].

Radar WebKit Bug Importer

Comment 8 2026-04-30 06:32:13 PDT

<rdar://problem/175939512>

Note You need to log in before you can comment on or make changes to this bug.