I'm hoping I'm not imagining things, but I'm fairly sure that I saw a clean 10.04 install with a key icon displayed in the menu bar. I believe it appeared when sudo was active for updating, etc. I don't seem to have this icon anymore, and I was wondering if it was something I removed inadvertently, or a problem because of the number of upgrades I've done.
If you know of this icon/functionality, please let me know.
The key icon is just to show you when you are using elevated or root privilege and gives you the option to drop those privileges. I don't see this icon all the time too and that is the way it is meant to be. As far as I can remember, I usually see this icon while installing something from the software centre or running something with root privileges.