In Ubuntu 12.04 LTS the ‘startup applications’ dialog by default doesn’t show any startup programs. I don’t know why that, but it’s inconvenient to customize your starting up services.
Disabling programs in startup applications dialog may speed up booting your Ubuntu. Don’t disable any program that you don’t know what exactly it does, it may cause problems. Some programs really need be enabled as startup applications.
To make Ubuntu 12.04 Show startup applications, run this in a terminal window:
sudo sed -i 's/NoDisplay=true/NoDisplay=false/g' /etc/xdg/autostart/*.desktop