In change workding calendar window:
Shift+mouse select & drag works within a month and across months on the same row in a view.
Dragging across consective months where the months are on different rows in the view does not work, selects a mass of dates
For example: December 2012 top right of window & January 2013 bottom left of window.
Attempting to drag from 20-Dec-2012 through to 4-JAN-2013