R help - Jun 2009 - Windowing issue with diagram package & R 9.1

I had strange windowing behavior with R 9.1 on Windows XP when executing code
from the diagram package.  Perhaps it is even normal behavior that I don't
understand as it was an unintentional discovery.  I don't even know if it is
a package issue or a windowing issue.

Reproducing it.  Execute the code fragment below from vignette(diagram) that
uses par() to draw a four panel "diagram".  The diagrams appears.  So
far so good.  Now roll the middle mouse wheel down and the diagram redraws as
only the lower left panel.  If I now resize the window device the four panels of
the original plot reappear.

Is this normal behavior or is there an issue.

Thanks,
Rob Baer

----------------------------------
Fr0m the diagram package vignette:
par(mar=c(1,1,1,1),mfrow=c(2,2))
 #
 #
 names <- c("A","B","C","D")
 M <- matrix(nrow=4,ncol=4,byrow=TRUE,data=0)
 pp<-plotmat(M,pos=c(1,2,1),name=names,lwd=1,box.lwd=2,cex.txt=0.8,
 box.size=0.1,box.type="square",box.prop=0.5)
 #
 #
 M[2,1]<-M[3,1]<-M[4,2]<-M[4,3] <- "flow"
 pp<-plotmat(M,pos=c(1,2,1),curve=0,name=names,lwd=1,box.lwd=2,cex.txt=0.8,
 box.type="circle",box.prop=1.0)
 #
 #
 diag(M) <- "self"
 pp<-plotmat(M,pos=c(2,2),curve=0,name=names,lwd=1,box.lwd=2,cex.txt=0.8,
 self.cex=0.5,self.shiftx=c(-0.1,0.1,-0.1,0.1),
 box.type="diamond",box.prop=0.5)
 M <- matrix(nrow=4,ncol=4,data=0)
 M[2,1]<-1 ;M[4,2]<-2;M[3,4]<-3;M[1,3]<-4
 Col <- M
 Col[] <- "black"
 Col[4,2] <- "darkred"
 pp<-plotmat(M,pos=c(1,2,1),curve=0.2,name=names,lwd=1,box.lwd=2,cex.txt=0.8,
 arr.type="triangle",box.size=0.1,box.type="hexa",box.prop=0.25,
 arr.col=Col,arr.len=1)
 mtext(outer=TRUE,side=3,line=-1.5,cex=1.5,"plotmat")
 #
 par(mfrow=c(1,1))
-----------------------

---------------------
Robert W. Baer, Ph.D.
Professor of Physiology
Kirksville College of Osteopathic Medicne
A. T. Still University of Health Sciences
800 W. Jefferson St.
Kirksville, MO 63501
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Robert,

It is a windows thing:

Try:

par(mfrow=c(2,2))
for(i in 1:4)plot(i)
par(mfrow=c(1,1))

and then scroll/resize.

Karline