Cannot Logout of Drupal!

I realized I can log into drupal using the forum usernames and password.
I also noticed that if I log into the forum, I am automatically logged into Drupal.

So I thought I'd use this to my advantage, and link all registration and login to the forum.
All is working fine except one thing:

I cannot log off Drupal!
I click 'Logout', and all I get is "Successfully authenticated from forum DB."

However if I click Logout while in the forum, I can logout, no problem.

Is there a way I can click logout in drupal, and it affects the forum as well (or just logs off drupal alone)?