Safari not highlighting and auto-scrolling down.

I Have just downloaded OS X Lion (After tedious downloading for 2 and a half days due to poor internet connection!!) i have noticed in Safari that if i select text on a web page and try to select more text further down (holding the trackpad click down and dragging) it will not move down to select more text... hovever it will auto-scroll up to select text,

could this possibly be a bug? i hope so because its very inconvenient. unless im doing something wrong??