UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Steps to reproduce the problem:
1. Go to chrome://settings/clearBrowserData
2. Open Developer Tools and switch to toggle device mode.
3. Click the drop-down menu.
4. Turn off the toggle device mode and click the drop-down menu again.

What is the expected behavior?
Drop-down menu should be expanded properly in step 4 and 5.

What went wrong?
(Step 4) With toggle device mode, a black box shows up instead.

Did this work before? N/A 

Chrome version: 53.0.2785.116  Channel: stable
OS Version: 10.0
Flash Version: Shockwave Flash 23.0 r0

Any page with drop-down menu has this issue, not just settings page.

Chrome Help Forum link
https://productforums.google.com/forum/#!topic/chrome/5k9ni8Psj68
 

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	Screenshot (6).png 195 KB View Download