She’s a smart cookie. : )
Forgot to say, one of the breeds used to create minpins is the dachshund, so her bed digging may simply be practicing hole-digging for vermin.
Dachshund and terrier, yes. And boy, are they a delicate and beautiful little dog!
The digging is a brand new thing, but the tumor could be invading some instinctive part of her brain that triggers the behavior...