Duplicate Rows when Data Binding with LINQ to Entities

Question

I have problems binding both a telerik RadGrid and a plain vanilla ASP.NET GridView to the results of the following LINQ to entities query. In both cases the grids contain

Answer 1

And if you wrap the link query in a parenthesis and use the .Distinct() extension?

public IEnumerable FindPersons(string searchTerm)
{
    DirectoryEntities dents = new DirectoryEntities();
    return (from dp in dents.DirectoryPersonEntrySet
           where dp.LastName.StartsWith(searchTerm) || dp.Extension.StartsWith(searchTerm)
           orderby dp.LastName, dp.Extension
           select dp).Distinct();
}