Currently, if I have RV open with footage in it, and I drag a new source onto the already open RV window, the options are:
Add Source to Session
Add as Layer
Please add a new option:
Replace with New Session
This option is needed when checking many render layers in a hurry. You don't want to have to close RV and open it for each render layer to be checked. You also don't want to have to navigate to the location of a render layer in a dialog box. You need to be able to keep dragging new render layers onto RV and have RV open the new render layer, discarding the previous render layer. I often have 30 or more render layers to check in this manner and I am usually in a big hurry to get through them all before handing them off to the comper.