Privatemsg overwrites page title for custom code. How do I correct it?
I guess the private message form sets the title directly. A simple way round it might be to cache the current title before you render the form, then set it back again afterwards:

$stored_title = drupal_set_title();
print drupal_render(drupal_get_form('privatemsg_new', $recipients, $subject));
drupal_set_title($stored_title);