Issue #2948790 by @katski : Operations: "Please select at least one item."

regcode.views.inc

@@ -37,6 +37,8 @@ function regcode_views_data() {
     'weight' => -10,
   );
 
+  $data['regcode']['table']['entity type'] = 'regcode';
+
   $data['regcode']['table']['join'] = array(
     'users' => array(
       'left_field' => 'uid',