Canonical is now allowing users to disable the global application menus, that are now displayed straight in Unity, and to display them inside the application.Canonical introduced global menus a few editions ago and users have just started to get used to it, but Ubuntu users will now be able to get the old style back.
The solution is not exactly user friendly, but at least it is there. You will need to install dconf-editor. Just open a terminal and enter the following command.
sudo apt-get install dconf-editor
After the installation has been completed, start the program and go into com > canonical > unity > unity-gtk-module
Users will see two entries there, one is called blacklist and the other whitelist. If you enter the name of an application into the blacklist field, it will force it to display the menu in the application.
You can now enjoy app menus from before the year 2010.