Visual Studio 2013, using UltraWinGrid v15.1: When I click the cell button it is not raising the click cell button event. What am I missing?

public mmTest()

{

InitializeComponent();

DataSet dsAllUsers = GetAllUsers(DummyConfig.ConnectionInfo); // calls a stored proc to get the data

DataTable dt = dsAllUsers.Tables[0];

ultraGrid1.DataSource = dt;

ultraGrid1.DataBind();

ultraGrid1.DisplayLayout.Bands[0].Columns["UserID"].Style = Infragistics.Win.UltraWinGrid.ColumnStyle.Button;

ultraGrid1.DisplayLayout.Bands[0].Columns["UserID"].ButtonDisplayStyle = Infragistics.Win.UltraWinGrid.ButtonDisplayStyle.Always;

}

private void ultraGrid1_ClickCellButton(object sender, Infragistics.Win.UltraWinGrid.CellEventArgs e)

{

MessageBox.Show("Button in " + e.Cell.Value.ToString() + " cell was clicked.");

}