spinner control visibility during autogenerate.

I have a themeddatgrid that autogenerates the columns. 

For example  I set one column as follows: 

DataGridDoubleColumn iSl = new DataGridDoubleColumn //new DataGridInt32Column
{
Width = 120,
Header = "Amount",
IsReadOnly = false,
Visibility = Visibility.Visible,
SpinnerVisibility = SpinnerVisibility.Collapsed,

PlaceholderText = "",

Format = "F2",
Binding = binding
};
e.Column = iSl;

However the spinner is still shown when the grid is displayed.  Is there somplace else I need to set the value?