Seeing the page structure as another 'properties window'

What's this doing there? its' a duplicate of whats' above.

Happened since RC 2

I had this when I first updated to rc3 on my laptop and had it in a single column. I did the reset panel sizes to try and fix that and it removed the duplicate. So I reckon that might be what you need to do.

Thanks guys, could fix it by just resizing it (drag the top) all the way to the bottom until it disappears.