UPDATE: Forget it. DataTable wasn't created at binding time. Just needed a bs.ResetBindings() after the table was available......

Hi,
In essence:

public class X
{
   public DataTable dt;
   public BindingList<Test> y;  
}

public class Test {public string Name;}

BindingSource bs = new BindingSource();
bs.DataSource = AnInstanceOfX;
cbo1.DataSource = bs;
cbo1.DataMember = "y.Name"
cbo2.DataSource= bs;
cbo2.DataMember = "dt.Name" // Name is a column

The first binding works, the second does not. Why?
FWIW if don't use the BindingSource it works. i.e:

cbo2.DataSource = AnInstanceOfX;
cbo2.DataMember = "dt.Name";

(P.S. this isn't actual code - just a simplified version of the problem)