OK, "unwanted" is maybe not the best choice of wording. With my desktop being two 1920x1200 24" monitors, my first "need" with websites is to use 100% of the available width so I do not have these silly white edges. So I change a lot of fixed with garbage designed for 1980 devices to use 100% instead of 640px. HTTP::Proxy to the rescue.
I just measured my Opera to have a current size of 1530px in width. When I want the code snippets in the threads to "fit" left of the right bar (from which I indeed block some content), I need to restrict the size. Not wanting the scrollbar actually means I don't want the need for the scrollbar, as then the other elements get scrolled out, e.g. the (--) and (*)++ radio buttons.
Enjoy, Have FUN! H.Merijn