Stylize datatables before widget is loaded in order to avoid flickering

templates/base/components/datatable/static/formtable/layout.ready.js.twig

@@ -50,6 +50,10 @@ var oTable{{ sListIDForVarSuffix }} = $('#{{ oUIBlock.GetId() }}').DataTable({
         {
             this.closest('.dataTables_wrapper').find('.dataTables_length').hide();
         }
+
+        // Set header and body datatables status as loaded
+        this.attr('data-status', 'loaded');
+        this.closest('.dataTables_scroll').find('.dataTables_scrollHead .ibo-datatable').attr('data-status', 'loaded');
     },
 });