Running 16.04 & Unity on a new Dell XPS13 laptop, freshly installed.
The menus for some apps (terminal, nautilus) are always shown below the app title bar.
Some other apps like Chrome or Text editor/gedit do show correctly at the top bar as it is supposed to considering the use of global menus.
This is weird as it does not happen for both userids configured on this machine. The other user desktop shows menu for all apps at the top bar using global menus correctly.
See pic. And nevermind the Macbuntu theme, I just installed it to test with it, but the same behavior was experienced before I did it.