Once you've paired a device it will show in the list, whether it is available or not. You can only remove it by forgetting it. This is distinct from discovering a new device, which will only show if that device is in range and set to allow discovery.
Devices that have been paired are in blue, and wills say Connected or Not Connected.
Devices that are in range, discoverable, but not paired will show up in black and say Not Paired.
