In the footer-extras.php enter:

<style>

.table-responsive { overflow: auto; width: 100%; height: 66vh; }   
.table  th { background:#eef; }
		</style>

<script>

$j('div.table-responsive').on('scroll', function() {
  $j('thead', this).css('transform', 'translateY('+ this.scrollTop +'px)');
});

</script>