Incorrect values of object.make_trail

[BruceSherwood]

e = ellipsoid()
b = box()
s = sphere()
c = cone()
p = pyramid()
cyl = cylinder()

print "ellipse make_trail = " , e.make_trail
print "box make_trail = " , b.make_trail
print "sphere make_trail = " , s.make_trail
print "cone make_trail = " , c.make_trail
print "pyramid make_trail = " , p.make_trail
print "cylinder make_trail = " , cyl.make_trail

Some of these values are shown as True, though the objects don't in fact leave trails. Evidently the make_trail machinery is working properly, but reading the value of make_trail gives incorrect results.