discussed here:The panel encountered a problem while loading "....
http://forums.linuxmint.com/viewtopic.php?f=55&t=73643
...with bug report here:
https://bugs.launchpad.net/linuxmint/+bug/783537
The culprit this time was the System Monitor (the CPU, network etc graphs on the panel). Being somewhat stupid, I pressed "delete" rather than "don't delete", and now it's no longer in the "Add to Panel" list.
Does anyone know how I can get it back?
(please note: I *do* have the gnome-system-monitor itself, but I can't set up the applet that runs on the panel)
Thanks in advance for your time!