I tried to create a forum layout with a sidebar last night too and I couldn't seem to get anything to display in the sidebar, only above or below the forum. Perhaps I'm missing something?
When looking at a thread from a forum referenced by the 'RecentNews' block on my portal is displays as follows:
The OP
The word 'Comments'
My recent news slider (that I want on the home page but it randomly appears in the thread?)
The actual comments
Reply box
Bottom blocks from my home page (what's this doing in the thread too?)
It's weird, it's like it's trying to apply the portal layout to the thread. Anyone know how I can either stop this being applied or hide all these blocks using css in the thread view?
You're defaulting to the portal layout on your forum. Set a forum layout in the ACP and tick the forum layout box.
(this has been covered before quite a few times)