Turn off your dishwasher, and turn the water valve under the sink to the "off" position.
Pull the dishwasher out of its fixture so that you have access to the appliance's side panels and back.
Open dishwasher's door, and remove the screws on the rear corners of the top panel. Remove the top panel.
Remove the screws on the dishwasher's side panels, and remove the side panels. Afterward, you will be able to see the metal hinge and springs that need attention.
Check whether or not the ends of the springs hook properly to the metal connectors on the dishwasher frame. A disconnected spring is often the cause of a sagging dishwasher door. If a spring is disconnected, simply hook it onto a metal connector.
Check the end of the metal hinge. It should be hooked into the latch on the interior of the dishwasher door. A disconnected hinge is also a common cause of a sagging door. If the hinge is disconnected, hook its end into the latch in the door.