fixed assigned column bug

app/assets/javascripts/samples/sample_datatable.js.erb

@@ -220,13 +220,6 @@ table = dataTableInit();
 // Enables noSearchHidden plugin
 $.fn.dataTable.defaults.noSearchHidden = true;
 
-// update datatable step on colReorder
-(function() {
-  table.on('column-reorder', function() {
-    table.state.save();
-  });
-})();
-
 // Updates "Select all" control in a data table
 function updateDataTableSelectAllCtrl(table) {
     var $table             = table.table().node();

app/datatables/sample_datatable.rb

@@ -382,6 +382,8 @@ class SampleDatatable < AjaxDatatablesRails::Base
     coli = item[:column].to_i - 1
     model, column = sortable_columns[sortable_displayed_columns[coli].to_i]
                     .split('.')
+
+    return model if model == ASSIGNED_SORT_COL
     col = [model.constantize.table_name, column].join('.')
   end