UserAgent: Mozilla/5.0 (X11; CrOS x86_64 9202.64.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.146 Safari/537.36

Example URL:
http://bayareafastrak.org (the login popup form closes when you try to type), also in Gmail in the popup label selection menu while editing a message.

Steps to reproduce the problem:
1. Open the login popup form at http://bayareafastrak.org
2. Click in the username input field
3. Start typing and the popup disappears. Only happens to me in Chrome OS, same plugins as in macOS (synced account).

What is the expected behavior?
The popup should not close.

What went wrong?
The popup closes for some reason.

This happens in other sites too: in Gmail when writing a message, you can open the popup menu at the bottom right (the downward arrow icon), then hover on "label" which opens the label submenu with the input field focused, then start typing. The popup menu will be closed, just like with the bayareafastrak website login popup.

Both of these only happen in ChromeOS.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 57.0.2987.146  Channel: n/a
OS Version: 9202.64.0
Flash Version: Shockwave Flash 25.0 r0