UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0

Steps to reproduce the problem:
Using the NVDA screen reader go to GMail standard interface.
Select a message using the arrow keys.
Press the context menu key on the keyboard.
Try to select the context menu item to move a message to a different InBox tab.

What is the expected behavior?
Full keyboard access should be available for all features.

What went wrong?
The contextual menus are not accessible using only the keyboard.

Did this work before? Yes 

Chrome version: 52.0.2726.0 (Official Build) canary(64-bit)  Channel: canary
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: 

Thanks for all the ongoing accessibility work!