/// <summary>
 /// event is fired when the 'AddButton' is clicked.
 /// </summary>
 private void AddButton_Click(object sender, EventArgs e)
 {
     // if the value for HasParentListEditorHost is true
     if (HasParentListEditorHost)
     {
         // Add a new item
         ParentListEditorHost.Add();
     }
 }