My content is positioned correctly when logged in (top of sidebar level with top of main content). This is because the main content is moved down by the presence of pageNavLinkGroup. When not logged in, pageNavLinkGroup is gone and my sidebar looks too low because the main content moves up.
CSS would be nice, but I doubt it exists:
.forum_view .sidebar .loggedin
.forum_view .sidebar .notloggedin
How is this normally done?