Revolution IDE: How to finish drawing polygons?

[peter9.smith at ps.ge.com]

As a newbie I've managed to start drawing a polygon by selecting polygon on
the tool palette, getting a cross-hair cursor, clicking on the card to draw
the shape I want.  However how you complete drawing the polygon is not
obvious (to me) and nothing I tried worked.  

Help.  I have tried the Rev docs and Google first.

Thanks for any enlightenment, Peter Smith.