I have added my list, "Approvers" to my "For a selected item" flow in "Owners" and "Manage Run-Only Users" but I still can't see it when I select an item in the Approvers list. The Flow is not in the default environment, but in an environment i created for client work. I then created a test Flow in this client environment on the same list with the "When an item is created or edited" trigger and it worked fine.
Then I created the "For a selected item" flow in the Default environment and it worked when I selected an item in the Approvers list, even without the Approvers list being listed as an "Owner".
What goes on here? Is this a BUG? Why can't Flow run a "For a selected item" trigger in an environment other than the Default environment???