On the bottom of the first mixer channel in my mixer on Reason. There is a little yellow thing (hard to describe if you don't know what it is). I am asking if anyone knows what this is, or what it does. When you click on any particular mix channel, it highlights with red line at the bottom of the mixer, only channel 1 on mine, has a yellow arrow with a dot in it, as well as the red line in that channel, why? does this mean or do anything? It doesn't drag or move, nothing happens when you click or hover you mouse cursor over it or anything. What is it?