DataTable with column selects filtering not reducing select content during filter

mozzak

I have implemented column filtering using dropdowns as shown in https://datatables.net/examples/api/multi_filter_select.html.

All works except that after I apply a filter in a column all other dropdowns still show all possible values before filtering but I was hoping they would also filter down the dropdown content to what is stil available in grid.

How can this be implemented ?

thank you.