Rust Around Rinse Aid Dispemser
To correct this remove the dispenser clean and let the area dry and paint the edge where the rust was cleaned away with a good epoxy paint and let dry. You can use the old gasket if it is one piece by coating both sides with a good gasket sealant, usually something that is 100% silicone sealant. I would NOT recommend using two gaskets, using a 2nd gasket will allow water to get to the metal edge of the door panel around the threaded nut and it will have a much harder time drying out and may really cause the door panel to rust out. KA, WP, D&M, HP, GE and many other dishwasher makers did not put a gasket on the inside for a reason, you also cannot tighten the nut properly and it may work loose and leak.
This same technique of using the silicone sealant can also be used with the old [ clean and dry ] gasket for the detergent dispenser, inlet air-gap and several other places on this DW.