I fit a lm model and look at the diagnostic plots. To see all 4 at once I split the plot area in a 2x2 matrix. If I want to add a line to the first plot, I can change with par(mfg=c(1,1)) , but the axes are wrong, and correspond to the last plot. Example: x<-rnorm(100) y<-2*x+rnorm(100) m<-lm(y~x) par(mfrow=c(2,2)) plot(m) par(mfg=c(1,1)) abline(h=1,col=2) abline(h=0.01,col=3) This also happens with other plots like plot.cox.zhp of the survival library. Any solution? -- Victor Moreno V.Moreno at ico.scs.es Servei d'Epidemiologia i Registre del Cancer Institut Catala d'Oncologia Gran Via km 2.7, 08907 Hospitalet, Barcelona, Spain Tel: + 34 93260 7434 / 7401 / 7812 fax +34 93260 7787 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._