Mail debbugger page tries to process all users as select option

In the _mail_debugger_load_users function(), called when user access the 'admin/people/mail_debugger' path, the module tries to load all system users with a valid email to populate the user's select element of this page's form.

The code responsible for this is:

    $options = array();
    $users = db_select('users', 'u')->fields('u')->execute()->fetchAllAssoc('uid');
    foreach ($users as $uid => $account) {
      if (!valid_email_address($account->mail)) {
        continue;
      }
      $options[$uid] = t('!name (!mail)', array(
        '!name' => format_username($account),
        '!mail' => $account->mail
      ));
    }

If the system has many users this page needs too much time too load or even a fatal error is fired (execution time exceed, memory exhausted... ).

Module should limit the number of users available or use a autocomplete widget.