In Ubuntu, the Startup Applications application can be invoked from the Dash to view, disable, enable or remove startup applications. It can be started from the shell by the confusing command: gnome-session-properties. However, this application does not actually show all the applications and background services that are invoked when you login to a new desktop session.
There is a global directory that holds other startup applications and services: /etc/xdg/autostart. The .desktop files here are also started on login to a desktop. If you would like the entries here to appear in Startup Applications, then edit the files and change their NoDisplay=true entry to NoDisplay=false. Once they appear in Startup Applications, it is easy to enable, disable or remove them.
Tried with: gnome-session-bin 3.9.90 and Ubuntu 14.04
