A correct way to set column width in datatable when there is ScrollY

Hello
When I set width for a column datatable using
<th style="width: 120px">Code</th>
and set up the datatable with scroll

scrollY: (screen.height - 435) + 'px',
scrollX: true,

I will have a problem with misalign between header and content.
Do you have an example of a correct way to set a column width for jquery datatable with scroll Y?

Thank you