FYI: Adhoc connections like this one (with a dot over it) always show up in the list once they've been connected to once. Even if the original transmitter isn't there, it's still in the list. I'm guessing that's because of a lot of devices that use this use it for one-time PnP setup, and stop transmitting once setup. Though if you are in range and explicity try to re-connect to change settings, most will link back up and change.

A good example, I have a Rovio at home that uses this method to do initial setup. Once setup was done, the adhoc network went away on my laptop, but the N900 remembered it. If I reconnect with the N900 though, it does wake up and let me reconfigure it.