Version: M53 Stable
OS: Mac OS X

What steps will reproduce the problem?
(1) Hit the green window control to maximize the Hangouts window to full screen
(2) Try to get out of full screen (e.g. by clicking the green window control again)

What is the expected output?
Able to somehow get out of maximized mode

What do you see instead?
No button to get out of full screen (at least, I can't see one; let me know if I'm missing something) :)

Not sure if you're the right person to assign to, but I found your name related to Hangouts. Feel free to re-assign to the right person!