Jason Collins-Webb provided this Tip for the lines gallery: If you normally double click to apply an arrowhead for example, and you want to create a double ended arrow (i.e. arrowhead at each end of the line, or even a double ended tail!), then first select the line, select the appropriate arrowhead and double click to get one end. Then hold the CTRL key and double click again to get the arrow at the other end of the line.