Why does the horizontal scroll bar appear when

On this site, a horizontal scroll bar appears if the browser is开发者_如何学运维 resized to a certain size. Here's an attached image of what I mean. Notice the horizontal scroll bar at the bottom and the image cutting off even though the backgrounds are set to repeat-x.

Anyone know what could be causing this?

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It is the iframe inside #fb-root element in facebook-like section, that has a width of 575px

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Very difficult to identify without code. Either post some code or install Chrome, right click and "inspect element" to find the offending element.

As above - there is clearly an element that has a width > than the body