I recently had an issue with the Network Manager Applet 0.8, and Indicator Applet 0.3.7 (applets were locked to panel and disappeared for no obvious reason could not get them back using add to panel or looking in applications, places, or system).

I removed said applets using Ubuntu Software Center and reinstalled.

Where do I find the reinstalled software (applets) so I can add it back to panel?

TIA,

System--> Preferences--> Startup Applications.

Thank you Nexus!

I found the Network Manager (NM) in this location, but not Indicator applet (IA).

Regarding NM. When I go to system > preferences > start up applications and click on edit for NM. In the command txt box it say "nm-applet --sm-disable" (w/o quotes). If I remove "--sm-disable" will this add the applet back to the panel?

Not sure where else to look for IA.

These applets were included in the original build (10.4 LTS), and disappeared for no reason. If I add a new user... The NM and IA applets are present.

Any other Ideas are greatly appreciated.

OK, so I just came across this question ... 9 months later.

I've experienced disappearing applets in Ubuntu. Tried various Terminal commands, none of which worked.

Solution I found : check Startup Items/Applications. I found that for unknown reasons some of the applets had become "unticked", so were not appearing on start-up. By ticking them, they appeared after a re-start.

Hope this helps.