Each location from the list can be flagged a favorite. You just mark the star at the end of the line of the location. With that, the favorite is accessible with one click in the favorite list.
When I created a customer shortcut, I wanted to make it a favorite. This is very intuitive: creating a customer shortcut means, I want to use it, often. I am surprised that I can't mark it as my favorite.
Could you please add this star to the custom shortcut line?