It is quite easy to manage startup applications in Ubuntu Wily Werewolf even though this functionality is not integrated into system settings dashboard. Just follow these instructions to start applications after login.

GUI – GNOME Session Properties

Go to top left screen corner. Open Dash Home and start typing startup in search bar to execute Startup Applications application.

Ubuntu - Dash Home

Use Startup Applications Preferences to easily manage startup applications.

Ubuntu - GNOME Session Properties

You can use gnome-session-properties command to directly start the above-mentioned application.

CLI – Desktop entries

In this example I will create Seafile applet desktop entry file to start it after login.

Create ~/.config/autostart/ directory.

$ mkdir -p ~/.config/autostart

Create seafile-applet.desktop desktop entry file and store it inside ~/.config/autostart/ directory.

$ cat << EOF | tee ~/.config/autostart/seafile-applet.desktop
[Desktop Entry]
Type=Application
Name=Seafile
Comment=Seafile applet
Exec=seafile-applet
X-GNOME-Autostart-enabled=true
Hidden=false
NoDisplay=false
EOF

Use X-GNOME-Autostart-enabled key to enable/disable application on startup.

References

Desktop Entry Specification