I'll call the vet's office this afternoon. I still suspect that it's a behavioral issue, because of the way it started when there was a new dog in the house; also, now that it has cooled down yesterday, she isn't acting lethargic anymore - she's acting like her usual goofy self! And I know that pack order and dominance are BIG issues on Pup's mind!
We've been "checking her out" for things like ear problems, back spasms, leg problems - the "typical" maladies that cause uncontrollable urination - and we haven't seen any problems. But, it's probably best to let the Vet check her out.
By the way, she had no accidents last night, but did have one this morning when my husband got out of bed an hour-and-a-half before we wake up. Once she's awake, she just can't hold it anymore! I wasn't even awake, or I would have let her out!


Thanks so much for all the advice!
And yes, retired racers are fabulous pets! Such sweet, loving personalities!