filter the_title problem in nav

Hi I have a problem with the_title filter:

I have this code at my constructor:

add_filter( 'the_title', array($this, 'change_title') );

and this as callback (for testing purposes)

 public function change_title($title)
 {
    return 'title';                 
 }

But is filtering my navigation items!
instead of show home, pages, etc all changed to 'title'

Any Ideas how to fix it?