That's a limitation with IE and the overflow option. It won't give the horizontal scrollbar unless you set overflow to scroll in which case the scrollbars show up even if they aren't needed.
As much as it pains me to do it I think I'm going to have to add in a wordwrap feature when a post is added to the database and force it to add a linebreak when a very_long_string_that_breaks_the_layout is encountered. I hate always acommodating for IE, but it's still widely used, so looks like no other choice.
