In Ubuntu, move the window's menu from the top bar back to the form itself, disabling the global menu

Ubuntu does not know from which version to start, the window of the menu unified run to the top of the screen, called the global menu.

This way on the small display is really good, save a lot of places, but for large monitors, the window is not full screen situation too much, this way is not full screen of the window is very unfriendly.

Because the mouse needs to run so far to the menu bar.

1. Open the terminal:
sudo apt-get autoremove appmenu-gtk appmenu-gtk3 appmenu-qt
When you're done, just close all the programs and reopen them to see the fruit.
But for Firefox, you also need to disable the "global menu Bar Integration" in "Extended components"-"extensions" to

Another: If not adapt, want to recover back: in the terminal input
sudo apt-get install appmenu-gtk appmenu-gtk3 APPMENU-QT
Also, the "global menu bar Integration" is enabled in the Firefox extension component-extension.
Turn off all programs and open them again.