I use a new MacPro with four output. I try to change the UseDisplayIndex, but nothing happen. How did this index work ?

Another question concern exact map. If i use the current source as preview, no problem; but if i use Layer 1 as preview, the media is flip with y axis and the option flip is set to OFF. Why ? and what is the exact sense of the top left w and h of the image source ? (number of pixel in the image source ....) It could be easier to fix if we can move the rectangle for example in the image space as we can do in the screen space.