Thank you Burt Gunter and David Winsemius, I confirmed David's comment. One must use type=c("p","g") in order to get both the grid and points.
So, to use densityplot well, we must be quite aware of the options for panel.xyplot! Cordially, Giles Crane ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.