(Application Menu / System tools / Preferences / Startup Applications)
I added two new applications,
however, I noticed that they did not start on the next startup.
This was because they were not added permanently to the Startup applications.
and this was because my ~/.config/autostart forlder's write permission owner was the root.
I changed this with sudo chown -R myuser:myuser ~/.config/autostart
Probably running sudo gnome-session-properties would also have been enough, but I did not try.