Diagnosis
That's hard water scale. This model has a built-in water softener that uses a special salt (not the same as rinse aid), but it needs to be refilled and regenerated. If you've never touched it, it's been running on hard water this whole time.
How to Fix It
Open the dishwasher, pull out the bottom rack, and unscrew the cap on the softener reservoir at the bottom of the tub (usually on the left side). Fill it with dishwasher water softener salt (like Affresh Dishwasher Salt) until it's full, then screw the cap back on. Run a 'Sanitize' or 'Heavy' cycle to regenerate the system. You'll need to do this every 1-3 months depending on water hardness.
If That Didn't Work
If the film persists, your inlet water might be extremely hard. You can try increasing the rinse aid dose setting (hold 'Sani Rinse' for 3 seconds to enter the menu) and using a dishwasher cleaner like Affresh to dissolve existing scale inside the machine.
Heads Up
Never use table salt or rock salt. It will ruin the softener unit. Only use products specifically labeled as dishwasher water softener salt. Also, overfilling can cause salt to clump; fill just to the top.