UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36

Steps to reproduce the problem:
1. Create or get a .html file on your system.
2. Open the file in Chrome.
3. Open the developer tools.
4. Go to the "Elements" tab of the dev tools.
5. Find the CSS Pane, and open its "Styles" tab.
6. Press the "+" button in the top right of the Styles tab to add a new CSS Rule.
7. Select a stylesheet if needed.
8. Type any CSS rule and hit enter.

What is the expected behavior?
The newly created rule appears empty (and grayed out, if it does not select over the element highlighted in the Elements tab), and can be double-clicked on to start adding style declarations.

This is the usual behavior on live websites, but it doesn't seem to work on local files opened through the file:// protocol.

What went wrong?
The rule disappears immediately as Enter is pressed, regardless of any modifier keys, and regardless of the selector used. The selector cannot be found in any stylesheet thereafter, and so cannot be edited to add style declarations.

Did this work before? N/A 

Chrome version: 64.0.3282.186  Channel: stable
OS Version: 10.0
Flash Version: