The appmenu (also known as the global menu) in Ubuntu Oneiric can be both a useful and annoying feature. When it is in action, it reduces the screen space required to render the menu bar. If you are using a computer with small screen, this is very useful for you. On the other hand, if you have a large screen, having to move your mouse to the top left corner of the screen every time you want to access the menu can be a troublesome chores.
For those who wish to remove the appmenu, simply remove the appmenu app with the following command:
Restart the PC. Your menu bar should stick to the top of your application window now.
If you are using Firefox, you will notice the above method will not work. This is because Oneiric is using a Firefox extension to enable the global menu effect.
1. In your Firefox, go to “Tools -> Add-ons -> Extensions”. Disable the “Global Menu Bar Integration” extension (You can’t un-install it).
2. Restart Firefox. The Firefox menu bar should stick to the application window now.
To re-enable the appmenu, all you have to do is to re-install the appmenu packages.
and restart your computer.