I really do not get how this works i have tried to understand form other threads but I dont get it. You use the screen spanning doctor? is it safe? you have to have the ibook open while using it? does it diplay the full desktop on the external screen or does it do a dual monitor thing where it uses both screens? what types of cables are needed? anything else nessacary to do this? Id be using an external monitor for more room with programs like photoshop.