I think this is a simple one. When editing a material, there is a little box that allows us to add a map to that parameter (diffuse, reflect etc.). That is great to maps things quickly, but it doesnt allow for dragging of maps, swapping, or instanced. We have to use the map section of the material for this. Its just faster sometimes to be able to drag from the top were the color swatch is.
thanks,
Travis
thanks,
Travis