Dear r-helpers, I have been bitten by a cryptic comment in the help page for xYplot(). Here is some code from Madeline Bauer, one of the authors, which is essentailly the code on the help page for xYplot(): # This example uses the summarize function in Hmisc to # compute the median and outer quartiles. The outer quartiles are # displayed using "filled bands" set.seed(111) dfr <- expand.grid(month=1:12, year=c(1997,1998), reps=1:100) month <- dfr$month; year <- dfr$year y <- abs(month-6.5) + 2*runif(length(month)) + year-1997 s <- summarize(y, llist(month,year), smedian.hilow, conf.int=.5) # filled bands: default fill = pastel colors matching solid colors # in superpose.line (this works differently in R) xYplot ( Cbind ( y, Lower, Upper ) ~ month, groups=year, method="filled bands" , data=s, type="l") The comment "this works differently in R" should be ammended to a more explicit danger sign (otherwise users like myself might find themselves wasting a great deal of time). There appear to be two differences between S+ and R here: (1) the default colors of the bands are not as expected (but they can be changed at will, so that's not a serious problem); (2) I have not been able get rid of the outline around the filled bands or change their colors to match the fill. I would have thought that ... xYplot ( Cbind ( y, Lower, Upper ) ~ month, groups=year, method="filled bands" , data=s, type="l", lwd.bands = 0, lty.bands = 0, col.bands = 'white') ... would do the trick. I even tried to fix the problem in the code of xYplot: > panel.XYplot function (x, y, subscripts, groups = NULL, type = if (is.function (method) || ... if (method == "filled bands") { if (.R.) grid.polygon(x = c(x, rev(x)), y = c(lower, rev(upper)), gp = gpar(fill = col.fill, col = col.bands, lty = lty.bands, lwd = lwd.bands), default.units = "native") else polygon(x = c(x, rev(x)), y = c(lower, rev(upper)), col = col.fill) } ... } Obviously I don't know grid well enough to fix the problem. Help would be much appreciated, as well as a more explicit warning on the xYplot() help page. There is, of course, the possibility that there's something wrong with my version of R or my OS or my machine. In that case a replication or non-replication of this problem on a different OS might alert me to this. R version 2.5.0 RC (2007-04-21 r41269) i386-apple-darwin8.9.1 locale: C attached base packages: [1] "grDevices" "datasets" "grid" "graphics" "stats" "utils" [7] "methods" "base" other attached packages: coda lme4 Matrix car cacheSweave stashR "0.10-7" "0.9975-13" "0.9975-11" "1.2-1" "0.3" "0.2-1" filehash digest circular boot gmodels multcompView "0.9-4" "0.2.3" "0.3-6" "1.2-27" "2.13.2" "0.1-0" reshape vcd colorspace effects Hmisc acepack "0.7.2" "1.0-3" "0.95" "1.0-10" "3.3-1" "1.3-2.2" HH multcomp mvtnorm JGR iplots JavaGD "1.18-3" "0.991-9" "0.7-5" "1.4-15" "1.0-7" "0.3-6" MASS gridBase lattice latticeExtra rJava xtable "7.2-33" "0.4-3" "0.15-4" "0.1-6" "0.4-15" "1.4-3" Thanks, Michael Kubovy