We have a custom light gray basemap that is shared to everyone. When I create a map in Arcgis.com the basemap is an option to use. However, when I open a map in a groups gallery map viewer, I do not have the option to access my custom basemaps (i.e. Switch Basemap) even when I am logged in with my AGO account. How can I make my custom basemaps available as an option within the Application Templates and Group Gallery map viewers?