[julia-users] Problems with Jitter in Gadfly

[r5823]

If I call,

plot(layer(x=c1, y=c2,Stat.x_jitter,Geom.point),
layer(x=c1, y=c2,Geom.boxplot))

I successfully generate a plot showing jittered data points overlaid on top 
of a boxplot. If I remove the boxplot layer and call,

plot(layer(x=c1, y=c2,Stat.x_jitter,Geom.point))

I get the following error:

LoadError: ArgumentError: reducing over an empty collection is not allowed
while loading In[350], in expression starting on line 11

 in _mapreduce at reduce.jl:139


Any thoughts on what is going on here?