Disappearing Scroll Bars when Not Logged In

I have tried everything I can think of and see nothing in the CSS that would be causing this.


But when I am not logged in my browsers Vertical scroll bar is missing.  Even if I  force it to be visible there is no scoll.  It is like the browser has no idea the height of the resulting page.


This is driving me nuts and I am sure it is something I am just overlooking.  I never had this issue with my theme until I moved to 1.6.1.