OK I went back and read then end of the previous thread and found that the One automatically adds the A, B, C button icons. I had labelled the buttons slightly differently which is why the didn't show up on my config.

Does Logitech (or anyone else) have a list of these "Easter Egg" buttons icons?

More to the point if we can add icons to the Favorite Channel buttons and Logitech can add them to other custom buttons why won't they let us add our own icons to any buttons. It should be very easy to program for them.