That was not a good way of knowing if Amethyst was using Tor or not because so much of what the app does does not show up on the screen. Just because the feed is empty doesn't mean that Amethyst is only using Tor. 

You can use something like  https://www.rethinkdns.com/ to monitor connections that apps make, including Amethyst. Both form using internal Tor and Orbot.