[amibroker] Can Only Get shapeUpArrow to Show Up

[davemabe2000]

I'm trying to add some shapes to my charts.  I can get a shapeUpArrow to 
appear, but when I try to switch it to any other shape nothing appears.

Here's my code:

H0 = Ref(H, 0);
H1 = Ref(H, -1);
L0 = Ref(L, 0);
L1 = Ref(L, -1);

PlotShapes(H0 < H1 && L0 > L1 * shapeUpArrow, colorRed, 0, H);


Changing shapeUpArrow to shapeDownArrow makes it disappear entirely (as far as 
I can see).

What am I doing wrong?