I decided to connect my Bose bluetooth headset to my Mac this afternoon so that I could work on sequencing without bothering anyone around me. The headset connects properly and tells me that it is connected. When I play a sequence in xLights, nothing comes through the headset ... despite having the headset selected as the output device in the settings control panel of the Mac. If I switch to iTunes (or other sound producing programs such as Youtube in Safari) on the Mac, the sound comes through the headset as expected. When I then switch back to the xLights program, no sound comes through the headset.
It seems that xLights doesn't pay attention to the control panel sound setting on the Mac.