[R] lattice color problem with symbols: bug?

[Stefan Grosse]

Dear useR's,

I have a problem with the lattice plotting of some symbols:

library(lattice)

test<-data.frame(x=c(2,3,1,5),u=c(rep(1,2),rep(2,2)),g=c(rep(c(1,2),2)))

xyplot(x~u,groups=g,
 data=test,
 par.settings=list(
    superpose.symbol=list(pch=c(22, 23),cex=c(1.7,1.6),col="black")
    ),
 key=list(
    text=list(c("t1","t2")),
    space = "bottom",pch=c(23, 22),
    points=F,
    cex=1.0,
    col="black"
    ),
)

As you see the symbols which have been plotted into the plotting area appear 
to have some filling color while in the legend there is no filling color 
although the specification of the symbols is the same.

If I use a normal plot command, the symbols are also not filled:
plot(c(1,2,3),c(1,2,3),pch=c(22,23,24),cex=1.5)

That problem must have occured during a recent lattice update since the color 
was not there when I was plotting a year ago with R2.5.x and some older 
lattice. It occurs on my linux as well as on my windows machine both with R 
2.6.1 and latest lattice from CRAN.

So here my questions: How do I get rid of the color? (or is it a bug?) If it 
is a feature, so how do I determine the color in both the symbols in the 
legend and in the plot itself? (Actually I was overlaying two plots e.g. one 
colored diamond and one empty diamond to achieve that effect but if there is 
a more efficient way to draw bordered symbols with customized color that 
would be preferable...)

Stefan