Tell new broadcast sessions what the current state is, just in case they

were added in the middle of an existing session.

lib/units/device/plugins/screen/stream.js

@@ -455,6 +455,10 @@ module.exports = syrup.serial()
           frameProducer.stop()
         })
 
+        broadcastSet.on('insert', function(id) {
+          broadcastSet.get(id).onStart(frameProducer)
+        })
+
         display.on('rotationChange', function(newRotation) {
           frameProducer.updateRotation(newRotation)
         })