Andreas and Bob thanks for the replies. I think I understand what you guys are saying. But I feel my question is still not answered.
I am sending effects FX1 to Mix 2 and I am hearing FX1 on Mix 2. I am not sending any effects to Mix 1 (FX1 return Master fader on layer 2 for Mix 1 is down). Why am I hearing FX1 on Mix 1.