User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:37.0) Gecko/20100101 Firefox/37.0 Build ID: 20150415140819 Steps to reproduce: 1. Open a YouTube video or Netflix video on OS X. 2. Press COMMAND+T or COMMAND+N or SHIFT+COMMAND+P. Actual results: The "File" menu item lights up with the blue highlight when the letter key of the shortcut is pressed, but nothing happens. Expected results: A new tab should have opened, or a new window, or a new private window, respectively.
This not only happens on OS X, but also on Windows. Is probably a duplicate of bug 78414.