I don't think it's a question of how long, but rather when were there windows on dishwashers. The Apex, as pictured, in the very early 50s could be ordered with a window in the cover. The Youngstown, also a top loader, had a window in the lid, at least on all of the models I have seen, but the window was much smaller. The portable version of the James had a lid that was basically all glass in a metal frame. The later version of the James was the front loading Ling Temco which had a glass door in a metal frame. After that, it was demonstration models in stores where there was either a bubble dome on the top loading portables or a plastic plug in the dimensions of the inner door panel and finally the all plastic tanks Maytag and KitchenAid (any others?) used in stores to show the washing action. Now there are some imported small counter top dishwashers and some models of those have a window in the door.