Node Reference - not show [nid] info

Hi everyone.

I'm managing a DRUPAL site where loged users can create content. In some of them there are 'Node Reference' fields, but when the name is selected appear '[nid: xx]' (XX -> intern DB code for that name) like this example:

>> John Smith [nid:10]

I'm not interested that this code appear to normal users, so can I solve it?

In some forums, I see this solution:
- file: "nodereference.module"
- Change the code:

function nodereference_autocomplete($field_name, $string = '') {

  foreach ($references as $id => $row) {
    ...
    //$matches[$row['title'] ." [nid:$id]"] = '<div class="reference-autocomplete">'. $row['rendered'] . '</div>';
    $matches[$row['title']] = '<div class="reference-autocomplete">'. $row['rendered'] . '</div>';                     //NEW CODE
}

I've changed it but it doens't work yet.

Thanks in advance.
SNOPA.