After your dishwasher is done cleaning the dishes and it's finished it's dish washing cycle and has rinsed the dishes and has shut off it is a good idea to open the door of the dishwasher and allow the dishwasher to air out.
Allowing air into the dishwasher helps prevent the dishwasher from smelling and growing mold in the dishwasher.
I always leave my dishwasher door open for a couple hours after I'm done washing the dishes in the dishwasher and it has helped keep my dishwasher from getting mold buildup and keeps the dishwasher from smelling.
You don't want to leave the dishwasher door open all the time but just when you get done washing the dishes and for a few hours to allow it to air out.
It just helps prevent the dishwasher from growing mold and helps the water in the dishwasher dry out and keeps your dishwasher smelling better.
You don't have to leave your dishwasher door open if you don't want too but it's a good idea to do so.