Thanks, I've now got the plot I was after. No idea what the stacking warning is about, but it does not seem to compromise my output. Gavin. -- View this message in context: http://r.789695.n4.nabble.com/Some-problems-with-back-to-back-bar-plots-in-ggplot2-tp4671744p4671765.html Sent from the R help mailing list archive at Nabble.com.