Can you please attach a screencast of the problem. Thanks.

I have uploaded a screencast at: https://drive.google.com/file/d/1WzUr8umUSskRF6ZaBJzPtTRL9i6jnI4m/view

Unable to reproduce this issue on reported version 63.0.3239.84 using Mac 10.13.1 with steps mentioned below.

1. Navigated to wikipedia.com >> Selected scrollbar and dragged it down and observed successful scroll.
2. Scrolled using touch pad -- observed successful scroll.
3. Now again dragged scrollbar and observed scroll.

@Reporter: Could you please check the video and let us know if we miss anything. And also could you please check the issue by creating fresh profile which do not have any apps/extensions.

Thanks!

Deleted: 794907.mp4 14.6 MB

	794907.mp4 14.6 MB View Download

Go to Apple menu > System Preference > General

There are three option for show scroll bars:

1. Automatically based on mouse or trackpad
2. When scrolling
3. Always

Select either 1 or 2 and you should be able to reproduce the issue.

For 3, scrolling works.

Thank you for providing more feedback. Adding requester "sc00335628@techmahindra.com" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Unable to reproduce the issue on reported version 63.0.3239.84 on Mac 10.13.1 with steps mentioned below

Steps followed to reproduce the issue:
1) Launched chrome reported version
2) Checked "Show scroll bars" to "Automatically based on mouse or trackpad" in System preference->General
3) Navigated to wikipedia.com and checked the behaviour of the scroll bar

@Reporter:
Change the "Show scroll bar = Automatically based on mouse or trackpad / When scrolling", after changing it please restart the browser for the changes to reflect, when scroll bar is in above two options, for the first time we need to scroll the page, scroll bar is not seen unless we scroll with touchpad once.

Please find the attached screen cast of above steps, and provide your feedback.

Thanks!

Deleted: 794907.mp4 9.8 MB

	794907.mp4 9.8 MB View Download

[mac bug triage] What device are you using for your mouse? A trackpad? A physical mouse?

It looks like the page was in a state where the scrollbar was stuck in a visible state (it was visible from the time you un-minimized the Wikipedia window). Have you seen Chrome get into this state again, or do you have a way to reproduce it starting from a fresh window?

(I also notice that you tested on macOS 10.13.0. It would be interesting to know whether it still happens on 10.13.3.)

This issue is present on macOS 10.13.3 as well.

For me this happens on every website when I first open it( whether in a new tab or same tab).

Thank you for providing more feedback. Adding requester "sc00335628@techmahindra.com" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Unable to reproduce the issue on chrome reported verson 63.0.3239.84 using MacBook Air 10.13.3 with steps mentioned below:
1) Launched chrome reported version and navigated to System preference->General
2) Checked "Show scroll bars=Automatically based on mouse or trackpad"
3) Navigated to wikipedia.com and checked the behaviour of the scroll bar
Even we have tried checking this issue on MacBook Pro 10.13.1, but unable to reproduce the issue.

@Reporter:
Please find the attached screencast for your reference, please check the issue on latest stable and report us back the behaviour. you can download latest stable from URL provided, URL:https://www.chromium.org/getting-involved/dev-channel

Thanks! 

Deleted: 794907.mp4 7.7 MB

	794907.mp4 7.7 MB View Download

Would you mind sharing a screen recording that shows the problem from the beginning, if possible (i.e. not un-minimizing a window that is already in a bad state)? It would also be great if you could try on Canary. Knowing what kind of pointing device(s) you have would also be helpful (as shrike@ asked).

Mac triage: WontFix issue without working repro steps or feedback.