Bug report. After a fresh reboot, I started Lanterne and managed to get Morse code repeat the three words I had typed in continuously even though the option was off (witnessed by another human). I did mess with the Preferences before using Morse code, but other than that I don't know what might have caused it; I can't reproduce it now. Getting out of Morse code and clicking on the Morse code button stopped the transmission. The light was red (as chosen by me).