[R] ggplot2: How to remove legend component for geom_errorbar() ?

[Carsten Jaeger]

Dear list (probably Hadley),

I'm trying to do a plot like the following, composed of bars and error
bars:

df <- data.frame(factor1=gl(2,5), factor2=gl(5,1), y=rnorm(10),
err=0.1) 
ggplot(df, aes(x=factor1, y=y, fill=factor2)) +
    geom_bar(position="dodge", stat="identity") + 
    geom_errorbar(aes(min=y-err, max=y+err), position="dodge",
width=0.1)

The plot obtained has a legend named "factor2", giving as expected the
colours used for the five factor levels of factor2. So far so good.
However, the legend also contains solid horizontal lines, obviously
representing the error bars. While I do not immediately see the sense of
a legend symbol for error bars, is there any easy way to turn these off?

Thanks,
Carsten