Diagnosing the problem, i.e. finding the source of the leak, was the hardest part. The best clue was the leak only occurred well into the cycle when the water was hot and steam was coming out the vent. I then assumed there was a bad seal and steam & condensed water was leaking down into the door. I replaced the vent duct & seal, a broken drip cover (an internal part in the door), and replaced a missing rinse aid cap. This stopped the leak.

Removed inner cover of door. Pried Vent Assembly from door, peeled off thin sponge gasket strip from inner door, installed new thin sponge gasket strip on inner door vent opening bottom, snapped Vent Assembly into inner door opening, reinstalled inner door cover to door.
Recommend removing Vent screen from inner door first to expose locking tabs of Vent Assembly to ease removal and installation of Vent Assembly. I assume vent cover will come off if pried with small screw driver. I didn't remove vent cover and had difficulty removing and installing Vent Assembly. (I did accomplish it though)