Hi,
I’m running the Ubuntu Mate 15.10 Beta release, up to date as of today. I started a Youtube audio stream through my laptop’s default speakers, and then plugged in USB headphones and tried to set them as the default output device using mate-volume-control. However, after selecting them, the Youtube audio kept playing through my laptop speakers. It wasn’t until stopping the video and restarting it that the audio came
out the selected USB headphones.
I assumed that mate-volume-control was broken. I’m not sure if this is a limitation or a newly introduced bug? But in Ubuntu (Unity) the default volume control utility switches all active audio streams immediately upon changing the default output device, which I believe should be the behavior of mate-volume-control as well.
Here’s the bug report I filed: https://bugs.launchpad.net/ubuntu-mate/+bug/1497107
Thanks for reading!