dishwasher keeps running when cycle is done

[rasputins fingerbone]

i have  a frigidaire dishwasher model: fghd2433kf1 about a year old . dishwasher runs through cycle , cleans dishes fine . but when finished , and it says "dry" on the front , it continues to run . sounds like the pump down below possibly . i noticed it because my sink was leaking and had apparently shorted out the bottom plug of the outlet under the sink . i plugged dishwasher into another outlet via a heavy duty extension cord , it ran through the cycle , made a couple squeaky noises in the process , but finished dishes . then it again kept running . i haven't noticed any codes on it while plugged in . any ideas ?