He put his hand over the fence to pet her, he has been
> introduced to her but I think Shannon in the house & Shannon loose in the
> yard is a whole different thing & she jumped up slightly & nipped him,

   Sounds like Shannon knows her property limits and the neighbor is a
little slow on the uptake.  Hopefully he'll remember, and hopefully he won't
sue.

   People!  Argh! Professor Henry Higgins bemoaned women not being like him.
I say, too bad people aren't more like dogs.

   Is the difference that in the house you were there and in the yard
Shannon felt she had to protect her territory alone?  A dog without its
master in its territory is more agressive than a dog when the master is
there (I guess because, as the alpha, the master is expected to initiate and
approve strangers so the dog can relax more and only "go to war" if the
master does.  Don't let Shannon see you bite the neighbor LOL).
   Another good thing besides Shannon's protective mode is evidence that
your place *is* Shannon's place...she knows it's her home and she belongs.
What a happy thing for a formerly homeless dog.  :D

Rini