[R] rpart postscript graphics, Mac OS

[Kaiser Fung]

I am running R on Mac OS X 10.2x.  When I create
postscript graphics of rpart tree objects, a tiny part
of the tree gets trimmed off, even when it has only a
few terminal nodes.  This happens even without fancy
but worse if fancy=T.  (This doesn't happen with
boxplot, scatter plots, etc.)  How do I fix this?

postscript("tree.eps")
plot(davb.tree, u=T)
text(davb.tree, use.n=T, fancy=F)
dev.off()

Thanks
Kais