Bug 239437

Summary:	AX: macOS "Show scrollbar" setting "when scrolling" not respected, when a website sets scrollbar width
Product:	WebKit	Reporter:	Christoph <cseelus>
Component:	Accessibility	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED INVALID
Severity:	Normal	CC:	andresg_22, simon.fraser, smoley, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	Safari 15
Hardware:	Mac (Apple Silicon)
OS:	macOS 10.15

Description Christoph 2022-04-17 12:16:29 PDT

The macOS "Show scrollbar" setting "when scrolling", which automatically hides scrollbars is not respected, when a website sets CSS scrollbar width via `::-webkit-scrollbar`

Comment 1 Radar WebKit Bug Importer 2022-04-17 12:16:37 PDT

<rdar://problem/91865092>

Comment 2 Smoley 2022-05-24 09:06:54 PDT

Thanks for filing, link to or attach a test case that demonstrates the issue.

Comment 3 Smoley 2022-05-24 09:15:11 PDT

Forgot to say please! Thanks again :)

Comment 4 Simon Fraser (smfr) 2022-05-24 12:28:53 PDT

This is intended behavior. If the page provides custom scrollbars via `::-webkit-scrollbar` then they are always visible.

Comment 5 Christoph 2022-07-23 10:29:39 PDT

Whats the reasoning behind this decision, e.g. why disregard the users OS settings?

Comment 6 Simon Fraser (smfr) 2022-07-23 12:07:31 PDT

Because overlay scrollbars have some behaviors that are not describable via custom scrollbars (e.g. they grow on hover).

In general, we'd like to deprecate custom scrollbars.