gmix auto-unmute behaviour

[mawbid simnet is]

I disagree with gmix's behaviour when you move the sliders on a
muted channel. It automatically unmutes the channel. This reduces
the usefulness of the mute button. If there's a really loud sound
playing, but the channel is muted, you can't lower the slider on
that channel without turning on the loud sound for a moment. I guess
this is why most mixer panels don't work this way.