A continuous drip is caused by a leaking hot and/or cold shut off or the cartridge on a single handle. It has nothing to do with the tub spout or the diverter. There can be a drip for some time just due to water from the shower head line coming back out by gravity. If you select "shower" after turning off the water, this should accelerat this process.
But again, if the drip is continuous, it is the valves.