More than 9 columns of header

hoachen

I tested the example from below (have 9 columns exact) but more than 9 columns header and it does not work. When more than 9 columns the search box will disappear and can't perform the search. I looked into the "dataTableFixedColumns.min.js" and the code are so complex to understand. Is there someone can point out which function can be modify to more than 9 columns headers?
https://datatables.net/extensions/fixedcolumns/examples/initialisation/two_columns.html