Whenever live monitors are involved and pre-fade auxes are used to send to them, as a live mixer it is imperative that the channel mute also mute the pre-fade signals to monitors. There is needed a button, just like the FMP to follow main Pan we need FMM for follow main mute. In a live situation, when a mic is not being used, then the mixer wants that signal out of the monitors too. Take for example a reed player with a flute mic an a sax mic. He is only playing one a t time, the other is muted until use, there is no desire to have that open mic feeding the monitors until the player is actually using the mic, then the monitor signal is important, but the rest of the time not. Same with vocals, if a singer goes offstage with the wireless mic to change clothes or something, we need to mute the mic and the pre-fade aux until they come back on.