Nhibernate Cascade=none is not working as expected

Question

I have two classes, Vendor and contact. Vendor is a parent of Contact. There's a one-to-many relationship between Vendor and Contact. I have set the cascading relationship between Vendor and Company as none. This means (at least to me) when I change a Contact for a Vendor and save the Vendor, this saving action should NOT cascade to the Contact and therefore, any changes I make to Contact should not persist to the database.

However, this is not the case. When I change the FirstName of a Contact and save its parent, the saving action is cascaded to Contact. For example using below's test function, I see a Contact with the FirstName = "This_new_first_name_should_not_be_saved". Initially, I did not expect to see this change persist to the database.

Am I simply misunderstanding how cascade works or is there something wrong with my code?

Test.cs

[Test]
        public void RemoveManyToOneAssociation()
        {
            var container = BuildContainer();
            var vendorRepo = container.Resolve<Repository<Vendor>>(); //Get respository
            var contactRepo = container.Resolve<Repository<Contact>>(); //Get repository


            var vendor = vendorRepo.FirstOrDefault();
            var contact = vendor.Contacts.FirstOrDefault();
            contact.FirstName = "This_new_first_name_should_not_be_saved"; 
            vendor.Contacts.Remove(contact);
            vendorRepo.Save(vendor); 
            //The saving action above should not cascade to contacts because we have set cascade to "none"

        }

Vendor.hbm.xml

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                   assembly="DataAccess"
                   namespace="DataAccess">


  <class name="Vendor">
    <id name="Id" type="int" unsaved-value="0">
      <generator class="hilo" />
    </id>
    <property name="VendorName" />
    <set name="Contacts" inverse="true" cascade="none">
      <key column="VendorID" />
      <one-to-many class="Contact"/>
    </set>
    <many-to-one name="Company" column="CompanyID"></many-to-one>
  </class>

</hibernate-mapping>

Contact.hbm.xml

 <?xml version="1.0" encoding="utf-8" ?>
    <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
                       assembly="DataAccess"
                       namespace="DataAccess">

      <class name="Contact">
    <id name="Id" type="int">
      <generator class="hilo" />
    </id>
    <property name="FirstName" />
    <property name="LastName" />
    <many-to-one name="Vendor" class="Vendor" column="VendorID"></many-to-one>
  </class>

</hibernate-mapping>

Vendor.cs

public class Vendor : Entity<int>
    {
        public Vendor()
        {
        }

        public Vendor(string name)
        {                       
            VendorName = name;
        }


        public virtual string VendorName { set; get; }

        public virtual ISet<Contact> Contacts { set; get; }

        public virtual Company Company { set; get; }

        public virtual void CopyTo(Vendor target)
        {
            target.VendorName = VendorName;
            target.Company = Company;
        }
    }

Contact.cs

public class Contact : Entity<int>
    {
        public Contact()
        {
            //it's not the best practice to initialize virtual properties in constructor but we're controlling 
            //the inheritance in this so doing this should be fine
            // http://stackoverflow.com/a/469577/89605
            FirstName = "";
            LastName = "";
        }

        public Contact(string firstName, string lastName)
        {
            FirstName = firstName;
            LastName = lastName;
        }

        public virtual string FirstName { set; get; }
        public virtual string LastName { set; get; }
        public virtual Vendor Vendor { set; get; }

        public virtual void CopyTo(Contact contact)
        {
            contact.FirstName = FirstName;
            contact.LastName = LastName;
        }
    }

Update *Repository.cs*

public class Repository<T> where T : class
    {
        private ISession _session;

        public Repository(ISession session)
        {
            _session = session;
        }

        public virtual T GetById(int id)
        {
            return _session.Get<T>(id);
        }

        public virtual T LoadById(int id)
        {
           return _session.Load<T>(id);
        }

        public virtual List<T> GetAll()
        {
                return _session.Query<T>().ToList();
        }

        public virtual T FirstOrDefault()
        {
            return _session.Query<T>().FirstOrDefault();
        }

        public virtual void Save(T entity)
        {
            using (ITransaction _transaction = _session.BeginTransaction())
            {
                 _session.Save(entity);
                _transaction.Commit();                
            }
        }

        public virtual void Delete(T entity)
        {
            using (ITransaction _transaction = _session.BeginTransaction())
            {
                _session.Delete(entity);
                _transaction.Commit();
            }
        }
    }

Answer 1

As you have already inferred, you are misunderstanding how cascading works. More precisely, how NHibernate works.

All changes you make to already-persistent entities are persisted on Flush.

A call to session.Save() on an entity retrieved using the same session is a NO-OP (I have to assume that's what your Repository<T>.Save() method does, as I don't have your sources)