1. Add a store with ID: A.
2. Set the price of an item
3. Click "New Store" again at the store list
4.Specify A as the Store ID.
5. Price an item
6. Observe that the original store A is overwritten
Since I'm specifying I want to create a new store, I'm not really expecting an existing store to exist and would want to be warned before completely nuking the pricing in the old store.