Since the removal of phosphates from dishwashing detergent, a lot of customers have been having this issue. My recommendation is adding a product called GLASS MAGIC to the pre wash cup. Use about a table spoon per load. Glass Magic has phosphate in it and breaks down calcium so that your detergent can work properly. If all the dishes are getting wet and the detergent is gone and disolved and the unit seems to be running correctly otherwise, I'll strongly urge you to try this. Also, prior to starting the dishwasher, run the sink by the dishwasher HOT until all the cool water is gone from the line, THEN start your dishwasher. Definitely buy some GLASS MAGIC though. It really helps a lot.
The EPA required all phosphate removal from dishwashing soap last year.
People with harder water are having a heck of a hard time with good cleaning results. Glass Magic does work.