I meant to thank Sparky for telling me where to find the model number.

Also, I wanted to emphasize, I love this dishwasher. It is by far the best I've ever owned; I've never once needed to pre-rinse or -wash; dishes and pots and pans come sparkling clean. It has all the features I need/want, and I don't want to have to buy a new one.

Have you tried doing the Cancel/Drain to see if any of the leftover water goes out?

Sometimes where the drain line joins together under the dishwasher it can clog there or where it connects to the sink/disposal drain.

Take the drain line off the sink/disposal and try running water in the dishwasher, then let it drain in a bucket. This will tell you if you are getting a "full force" drain out. I read a tip to clean out the drain line, run a plastic ice maker water line (1/4 inch)up inside the DW drain line all way to the pump. This way if there is food/gunk blocking or partially blocking the line this will move it. Then fill the DW and do a drain to see if anything comes out. You may need to take it apart on the inside and clean the chopper and sump area. I would try the drain line in a bucket first to see how much flow you have on drain, then go with cleaning out the drain line if needed, then sump etc. Hope this helps..

If you have an air-gap on the sink there is a good possibility that this is where the blockage is.
Remove the cap. (usually chrome) and then remove the top of the air gap. ( some are screwed on some are held in by clips). Place a cup over the gap and then while holding the cup put the d/w in a drain cycle. DON"T let go of the cup!!!
You have now flushed the drain line.
Reassemble the air gap and everything should now be fine.
This is really one of the more common d/w issues I run into.

jakvis, our old sink had an air-gap; I know what you're talking about. Our new sink doesn't have one, though.

sparky, DH did the Cancel/Drain as you suggested, and all the water went out! We are so relieved. Does this mean we'll need to continue doing this, or should it be okay from now on?

THANK YOU both so much for your replies. :)

You (or DH) can look up the model number at SearsPartsDirect.com to see a breakdown diagram which will help if disassembly is needed.

As others have suggested, you can check the drain function by disconnecting the drain hose from your sink plumbing and running it into a bucket. That will confirm if the machine itself is able to drain OK, whether there may be a blockage in your plumbing connection. There are of course multiple fill/spray/drain periods throughout a full wash/rinse cycle, and there's no difference between one drain and another, they all work the same way. When dirty water is left behind, could very well be from the early wash periods that didn't fully drain. Overflow protection will prevent the machine from flooding if it goes into a fill with water left in the tub.

Per the diagrams this machine appears to be a power-clean type of unit (not tall-tub) with a unitary pump mechanism (tall-tub machines usually have separate recirculation and drain pumps), a macerator and soil separator chamber, which are known to perform quite well. The macerator screen can get clogged with fibrous debris, stray paper labels and such, which impedes water flow for washing/rinsing and could also affect draining.

dadoes, so good to see you here!

I really think something in the d/w is clogged, as some food is now being re-deposited on the dishes. Not much, but any is too much.

I forgot to say earlier, this is a portable dishwasher -- full size, just like the same under-counter model (which is called a Tall Tub d/w). Does that change any of your advice? Does that website show diagrams for portable dishwashers? If so, either DH or I will definitely look up the model number to see the diagram. I will also pass along to him what you said here.

THANK YOU.

There'd be no appreciable difference in the pump mechanism on a portable vs. undercounter unit of the same model/line. Only difference is that a portable unit has an outer cabinet to cover the tub and works so it looks nice parked in a corner or in-use at the sink. :-)

Whirlpool has unfortunately closed their tech website to public access, but I'll check if I had already saved a service manual that would be relevant to your model.

If your unit is a portable the clean out drain line advice still applies, it's just going to be harder.
The blockage is going to be at the device that connects to the sink. Many of these devices cant be taken apart but your blockage will be where the drain line is connected to the plastic piece. It makes a "hard" 90 degree turn and the blockage occurs there. In a worse case it may require replacing the fill drain hose assembly.