[R] eliminating panel borders from lattice plots

[John Bullock]

I am trying to eliminate panel borders from my
lattice plots.  By default, they always print.  For
example:

    library(lattice)
    x <- seq(-3,3,length=1000)
    y1 <- dnorm(x)
    y2 <- dnorm(x, sd=.5)
    data <- data.frame(x=rep(x,2), y=c(y,y2),
        panel=rep(c(1,2), each=1000))
    dplot <- xyplot(y~x | panel, data=data, strip=F,
        scales=list(draw=F))
    print(dplot, scales=list(draw=F))

prints borders around each panel.  I see no way to
get rid of them short of creating a panel function
and "painting over" these default borders with
grid.rect().  But I suspect that there is an easier
way -- is there?

I searched the archives but saw nothing on this.
I'm running R 2.3.1 with lattice 0.13.

Thank you,
--John