Here are some theories about this:
1. She is anxious
2. She is making her new surroundings more familiar.
3. She does not recognize that this is MY den, not hers.
What to do about it:
1. Put her in her kennel while we're gone. Check.
2. Walk her. Check.
3. Assert myself as the alpha female. Whatever.
I'm going to have to study this a bit more.