How to disable the app menu functionality ("global menu") in LibreOffice, Ubuntu 12.10?
Let me quote an answer from How do I enable or disable the global application menu?. This is how you disable the app menu on a per application basis :
To disable appmenu support on a per application basis, set the UBUNTU_MENUPROXY variable to null, with:
env UBUNTU_MENUPROXY= eclipse
the env keyword is useful if your trying to launch the application with the ALT-F2 shortcut.
You'll find more details on https://wiki.ubuntu.com/DesktopExperienceTeam/ApplicationMenu#Troubleshooting.
If you want to remove the "global menu" just for libre office this could work:
sudo apt-get remove lo-menubar
If you want to remove the "global menu" from ALL applications you should do the following on the terminal:
sudo apt-get remove appmenu-gtk3 appmenu-gtk appmenu-qt
If you want to put it back then use this on the terminal:
sudo apt-get install appmenu-gtk3 appmenu-gtk appmenu-qt
I hope this could help you. Good luck!