UserAgent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36

Steps to reproduce the problem:
1. open options.html in Chrome
2. press Enter or click OK
3. popup with message "Please fill out this field" will be shown
4. install extension
5. go to Options
6. press Enter or click OK
7. no popup will be shown

What is the expected behavior?
popup with message "Please fill out this field" should be shown

What went wrong?
popup is not shown

Did this work before? N/A 

Chrome version: 49.0.2623.87  Channel: stable
OS Version: 10.0
Flash Version: 

Popup is shown if we add
"options_ui": {
  "open_in_tab": true
}
in manifest, or if we use old way to declare options
"options_page": "options.html"

If nothing is entered in input, :invalid CSS selector is applied and onsubmit event is not fired, if OK is clicked or Enter is pressed. So Chrome takes notice of 'required' attribute, but doesn't show warning popup, when options dialog is displayed using new way.
 

Deleted: required attr test.zip 889 bytes

required attr test.zip 889 bytes Download