Change behavior when adjusting ‘additional outputs’ for the first time

When you have a bitmap plugged into something like corona color adjustment or corona mapping randomizer, and then you add an additional output it unplugs your first map from the material. No real reason for this and in a complex scenario it complicates things. Once you have added at least one additional map it stops unplugging maps anyway, so it would be nice if it had this behavior from the beginning.