More responsive Cancle button please.

When I am copying large files (1-3GB) and I hit the cancel button nothing happens. Sometimes when I hit it the job stops after it finishes copying whatever file it was in the middle of. Other times it never stops. The cancel button needs to be more responsive.

Furthermore if I hit cancel it should stop right where it is and delete the temporary file that it is currently copying. It shouldn't say, "Wait; I'm almost done; just let me finsih." If someone hits cancel it might be an emergency, in which case it needs to be responsive.

Thanks