OS X browsers option maximize\zoom
I think you are mixing up keys.

This is in El Capitan - earlier versions behaved differently - I forget when it changed

I have tried this on Firefox, Safari, Numbers and iTerm2


Cmd + green button makes the window full screen with no menubar
Alt + green button keeps the menu bar and makes the window fill the rest of the screen


these are documented in this Apple knowledgebase article

but 


Alt + Shift+ green button seems to do different things.


Safari Nothing
Firefox same as 2
Numbers same as 2
iTerm Keeps the menubar makes the window full screen height but keep the same width as before.