UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36

Steps to reproduce the problem:
This codepen reproduces the issue:
https://codepen.io/psant/pen/POJqov

Use a mac with a trackpad, where the scrollbars only appear during a scroll operation

1. In the codepen, scroll horizontally on the gray square
2. Hover over the horizontal scrollbar

You will see that the gutter does not appear and you cannot grab the thumb for dragging/scrolling.

What is the expected behavior?
When hovering over a scrollbar that fades in/out the scroll gutter should appear and the thumb should increase in size. The user should be able to grab the thumb. This is what happens on Safari and Firefox.

This works on the vertical scrollbar in Chrome.

What went wrong?
After the scrollbar fades in, and you hover over it with the cursor, the gutter never appears and you can not "grab" the thumb by holding the mouse button down.

This does work on the vertical scrollbar

Did this work before? Yes not certain, I believe this was working in chromium 57

Chrome version: 62.0.3202.94  Channel: stable
OS Version: OS X 10.12.6
Flash Version:
 

Deleted: ChromeScrollbarBug.mov 239 KB

ChromeScrollbarBug.mov 239 KB Download