Presets for Nav and Radio

I noticed that when I touch the preset buttons I can see what station is preset for that button. There are other times when I touch the same button, it doesn't show me the radio station but a Nav preset address that my dealer created. I do not know what I had touched to make one or the other show.
How can I create presets for Radio and Nav addresses whereby one button is good for both.

Page 20 in the manual details the function of memory buttons.