To clarify, at 3:40 in the video (in v7 at least) after selecting 'add a rectangle' click once to anchor one corner of the rectangle, then after moving the mouse pointer to where you want the opposite corner click a second time to create the rectangle. It is not click / drag / highlight as the verbal instructions seem to suggest. There is an almost imperceptible click when the rectangle is created, but not when the first corner is set.
