The drain line loops up to the top of the counter and over.
I think it is supply water filling the tub, because when I shut off the water supply it doesn't do it. So, I removed the water supply valve off of the dishwasher and blew through it. It seems to be sealing off well. I guess it doesn't leak, so what can be the problem that the d/w basin fills up with water in a few days and leaks onto the floor? The hose connections to the valve do not leak either.