> Under 'Output Devices', each output has three icons on the top right of > its 'box'. The first from the left is the mute icon, the second is the > lock icon (looks like a shield) the third which is a green circle with a > white tick is the 'set as fallback' icon. I apologize, but now I'm lost. Are we talking about the same user interface? I see nothing like this in System > Preferences > Sound : Output.
