/// <summary>
///
/// </summary>
/// <param name="newItem"></param>
/// <param name="title"></param>
/// <param name="productList"></param>
public Dialog(InvoiceItem newItem, string title, ProductList productList)
: this(newItem, title, productList, 0)
{
}
/// <summary>
///
/// </summary>
public Dialog(ProductList productList)
: this(null, "Add Fields", productList)
{
}