Bug 199451

Summary:

scrollLeft can become positive in vertical-rl writing-mode when -webkit-scrollbar is used

Product:

WebKit

Reporter:

Frédéric Wang (:fredw) <fred.wang>

Component:

Scrolling

Assignee:

Nobody <webkit-unassigned>

Status:

NEW ---

Severity:

Normal

CC:

cathiechen, simon.fraser

Priority:

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Bug Depends on:

Bug Blocks:

161611

Attachments:

Description	Flags
testcase	none

Description Frédéric Wang (:fredw) 2019-07-03 09:59:02 PDT

Created attachment 373393 [details]
testcase

See the attached testcase.

The elements have writing-mode vertical-rl and so scrollLeft goes from 0 (right) to left -200 (left).

However, when using -webkit-scrollbar, it is possible to make scrollLeft take a positive value. 

Note that this issue does not seem to happen with other writing-mode / direction values or when -webkit-scrollbar is not set:
https://people.igalia.com/fwang/scrollLeft-scrollTop.html

For now Cathie added a workround to https://w3c-test.org/css/cssom-view/scrollIntoView-vertical-rl-writing-mode.html to make the test pass in WebKit (it seems -webkit-scrollbar is used when using WebKit's layout test runner)