Diagnosis
Incomplete drying and residue are linked. The most common cause is use of rinse aid in combination with the AutoDry door-opening feature being disabled or malfunctioning.
How to Fix It
First, ensure the AutoDry function is active. The setting is controlled by the button with a fan icon. The indicator light should be ON. Second, confirm rinse aid dispenser is filled. Third, load dishes so water can sheet off; plastic items on the bottom rack block heat rise.
If That Didn't Work
The mineral content (hardness) of your water may be very high. The film is likely mineral deposits. Adjust the rinse aid dispenser setting to a higher number (more aggressive). If set to maximum (6) and problem persists, consider a water softener.
Heads Up
The Extra Dry option only extends the fan time. It does not increase heat. For best drying, always use a rinse aid and ensure AutoDry is enabled to allow moist air to escape.