Chrome Version: Google Chrome 66.0.3359.67
Chrome OS Version: Platform 0452.30.0 (Official Build) beta-channel chell
Chrome OS Platform: HP CHROMEBOOK 13 2016 (16GB) 
Network info: N.A.

Please specify Cr-* of the system to which this bug/feature applies (add
the label below).

Steps To Reproduce:
(1) Click your gmail tab in Chrome
(2) Use mouse scroll button to scroll up/down through the inbox
(3)

Expected Result:
You can scroll up/down in the mail box view

Actual Result:
Up/down scroll with the mouse scroll button does not work, disabled.

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)

When you open a new browser tab for gmail, all works as expected. After a while (in this particular case about 24h hours after opening the tab but seems somewhat random) the scroll button stops working. This appears to happen mostly in gmail tabs, although I think I saw some problem in calendar tab a while ago. It never recovers.

What is the impact to the user, and is there a workaround? If so, what is
it?

You have to open a new gmail tab and scroll button works again until it does not.

Please provide any additional information below. Attach a screen shot or
log if possible.

For graphics-related bugs, please copy/paste the contents of the about:gpu
page at the end of this report.