I am not sure if my dishwasher has been installed correctly. There is about 1/2 gap from top of dishwasher door to the countertop, not sure if this is standard? The controls for the dishwasher are on top (hidden controls) of the dishwasher door. Also, when I read the installation book for the dishwasher, it shows the drain hose raised higher than the garbage disposal before it gets lowered to be connected to the garbage disposal. I do not have an air gap setup underneath my sink cabinet.

I read about dishwasher siphoning if the drain hose is not raised.. Any thoughts on what I should do? Should I have the install person come back to raise the dishwasher drain hose?

The drain hose goes above the garbage disposal; however, garbage disposals have an inlet at the top for the dishwasher drain to be used when there is no air gap. The air gap referred to here is a device where the drain rises to the air gap then drains down into the drain. It prevents water from siphoning into dishwasher. Look at this manual which explains it a little better: http://dl.dropbox.com/u/8010163/LG%20Dishwasher%20Repair%20Service%20Manual.pdf
I hope this helps. If you fill your sink then pull plug to drain does water flow into dishwasher? If not, it should be fine.