Reverted accidental comment that disabled arrow scrolling
Reverted accidental comment that disabled arrow scrolling

edulan/react-virtualized,nicholasrq/react-virtualized,bvaughn/react-virtualized,nicholasrq/react-virtualized,edulan/react-virtualized,cesarandreu/react-virtualized,cesarandreu/react-virtualized,bvaughn/react-virtualized