For some reason we have been having trouble with our dishes becoming white.
Some reasons for white residue is:
Too much detergent
Detergent not disolving properly
We are going to try this but ehow.com says to soak your white residue dishes in white vinegar for 30 mins then rinse and dry.
Ways you can help prevent the whiteness:You can also put 1/4 cup of white vinegar in the dishwasher when starting a load. (they said to put it in a cup/bowl in the top rack).
Sometimes you can run the water in your sink to heat up the water in the dishwasher when it goes.
You can also try running the dishwasher with no dishes to help clean it as well.