[pulseaudio-discuss] volume-independence on secondary output devices

[Jud Craft]

> 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.