People Permission: View own unpublished content do not work I want let anonymous user can visit unpublished content, So I enable View own unpublished content for anonymous user.

But I open other browser to visit the url of unpublished content. But it alert me: 

Access denied 

I clear the cache, but above problem again

So, It is a bug?
Drupal 7
  
  In Drupal 7, users are not allowed to view any unpublished content by
  default, not even content created by themselves. By enabling 'View own
  unpublished content', you grant users access to their own unpublished
  content.
  
  The only way to allow users access to all unpublished content in
  Drupal 7 (without using a contributed module), is to enable the
  permission 'Bypass content access control'. Use this permission with
  extreme caution as it has far more consequences than just allowing
  access to unpublished content. In combination with Organic Groups for
  example, this permission allows access to private group content
  regardless of whether the user is a group member.


https://drupal.org/node/1106606

On that page are some contributed modules to set permissions you need...