UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:49.0) Gecko/20100101 Firefox/49.0

Steps to reproduce the problem:
1. Create a new window from a chrome extension with the type set to popup, panel or detached_panel (using the chrome.windows.create API)
2. Once the window is open, make it full screen
3. Hover mouse to top left corner, the toolbar buttons do not appear (the red, yellow and green toolbar buttons)

What is the expected behavior?
The toolbar buttons should appear

What went wrong?
The toolbar buttons do not appear

Did this work before? No 

Does this work in other browsers? N/A

Chrome version: 53.0.2785.143 (64-bit)  Channel: n/a
OS Version: OS X 10.11
Flash Version: