WPF DataBinding is terrific and allows for very passive views and easy source object updates. However, triggering updates in the view based on changes in the source object can be a little tricky.
If you want to make sure changes to your source object are reflected in your view, your source object will need to implement INotifyPropertyChanged (see example). Yet just implementing this property will not necessarily update your bindings. If your source object includes collections, and you bind to properties in those collections, you can update the source property but will not get updates from the source property, even if it is of a type that implements INotifyPropertyChanged.
The above scenario is common with Linq to Sql when the entities are generated for you. Even tables with one-to-one mappings will be generated with lists–as SQL doesn’t have a way of representing one-to-one relationships–so be sure to edit your dbml accordingly in order to take advantage of binding to your source object’s properties. (You might also consider removing some relationships to remove issues with DataContext collisions when trying to set properties of one Linq entity to another.)
If you can’t fix the problem this way or want to display the collection and changes to the collection, you can always add an ObservableCollection to your PresentationModel or wrap the source object with another object that does use the ObservableCollection to display your collection.