The Facilitate Serendipitous Discovery (FSD) command is undocumented (in Help file), but it's been revealed by Logos employees numerous times and is documented in the wiki in this page: https://wiki.logos.com/Desktop_Commands
You're supposed to be able to add "in {Collection}" to the end of the command to have Logos open to a random location in a random resource within that collection. But this variation does not work. It doesn't even recognize FSD as Facilitate Serendipitous Discovery if you add a collection parameter to it.

If you type in the full command name with the parameter, at least it recognizes the Facilitate Serendipitous Discovery command, but choosing it will not restrict the FSD command to that collection.

It opened to a random place in a book that is not in my Prayers collection.
