Where has my ErrorProvider indicator gone?

[penguin5000]

Hi, I'm using a variation of the following code from MSDN. I have conditions that are being met, and can display a message box to prove to myself that its reaching that point, but I'm not getting an ErrorProvider exclamation mark now that I've formatted the columns in my DataGridView to be numeric. The MSDN Code (from http://msdn2.microsoft.com/en-us/library/0ye0dkkw.aspx) is: MSDN Snippet: Private Sub Customers_ColumnChanging(ByVal sender As Object, _ ByVal e As System.Data.DataColumnChangeEventArgs) ' Only check for errors in the Product column If (e.Column.ColumnName.Equals("Product")) Then ' Do not allow "Automobile" as a product. If CType(e.ProposedValue, String) = "Automobile" Then Dim badValue As Object = e.ProposedValue e.ProposedValue = "Bad Data" e.Row.RowError = "The Product column contians an error" e.Row.SetColumnError(e.Column, "Product cannot be " & _ CType(badValue, String)) End If End If End Sub Why would formatting my columns break the ability to display the icon?