Hi Ajmaudio

My understanding of it is that it is for use with the Use Mix feature found when selecting the Folder.

Rather than having to find some spare space on the screen to put a mix of whatever size, you can have a 'virtual' mix set up in the Render options that doesn't actually show up on screen.

You assign layers to the hidden mix, then when you use Use Mix in a layer using a 'real' mix, all of the nested layers appear together with whatever effects and colours you have chosen.

Does that make sense? This is how the function appears to work - maybe I will be corrected.

Nev.