if you view comments in nested view, the nested tables extend to the right past the parent table. should be an easy fix.
I realized that was a problem when I was first developing the nested view. I know at one point I had something in there that would adjust table width to make it a little skinnier as it went further into the thread, I dont' remember if I left it in or not (it's been a while since I did that part of the code). I think as long as tables are nested using the UL tag (or OL tag for that matter), that it will just be a battle against the browser.