@Eric > That is a feature that is implemented only on the entry-level products such as the SB and WeGO, but also by certain software applications should they also control the audio output. Fortunately this doesn't exist on the higher level products as every time I use my WeGO it infuriates me that I'm listening to the Master to hear the mix, I finish the crossfade and BAM! The channel I just faded-out is in my ears at full volume again.
Unfortunately there is no way to change this function, especially as the SX has four channels.