draw2d line type dots?



I can't get draw2d line_type = dots to work ; just get a solid line.
my context is the ver 5.13, winxp, code:

doplot():=
  block([numer,p1],  numer:true,  p1: [ [0,0],[5,5] ],
 draw2d(points_joined = true, line_type = dots, points(p1) )
 )$

TIA

Ted Woollett