I'm worried about the state of this function.  This function is also used for thumbnails so if we're changing it for two-up that's going to screw up the intended logic for them.  We're adding all these special cases when it was meant to be a generic function to get visible elements within another element.  It should be possible to make it generic again, we know what div the elements are in and we also know all the coordinates, widths and what not so it shouldn't be hard to figure out what elements are visible.