A couple of years back I ran into an issue where a Polycom Touch Panel paired with an HDX-8000 Codec displayed a set of icons saying that 'No Sources' were selected for it. Attached is the picture of this.
I ran into this issue again yesterday, and this time on the Touch Panel, I did a factory reset, loaded the software again and paired it to the HDX. This took care of the issue and I was able to again choose either the USB for People + Content IP, or to use the VGA to DVI cable.
Just in case anyone has run into this; it is pretty rare for me, but this did the trick.