Chrome Version:63.0.3239.116/10032.75.0 Candy,Reks & Daisy
OS:chrome OS

What steps will reproduce the problem?
(1)Recover Build ->go to Sign into your Chromebook overlay
(2)Click 'More Options' ->Create account ->Enter First name,Last name
(3)Go to Verification code check by phone number overlay ->Open & close country codes drop-down
and Observe at R.H.S of drop-down while closing(Please refer video)

Actual:weird trace is seen at R.H.S of drop-down while closing it
Expected:No such traces should be seen while closing the drop-down

This is a Regression issue as same is working fine in M-60

Note:
1.Issue is also seen in latest M-65
2.Issue is not seen in Linux,Windows OS
 

Deleted: actual.mp4 12.8 MB

	actual.mp4 12.8 MB View Download

Deleted: Expected.mp4 8.1 MB

	Expected.mp4 8.1 MB View Download