R: ggplot2, why does my legend show faded colors?

Question

Why is my legend faded in these examples below? Notice how the colours in the legend are not as vivid as the colours in the plot:

library(ggplot2)
r <- ggplot(data = diamonds, aes(x = carat, y = price, color = cut, group = cut))
r + geom_smooth() #(left)
r + geom_smooth(size = 2)  #(right)

EDIT: added a close-up

Answer 1

I think they are the same colour - it's the different surrounds that make them look different.

Answer 2

I have the exact same problem, and it was not fixed by updating from 0.8.3 to 0.8.7. Did I not update the package correctly? The CRAN binary list of packages (in the OS X gui) lists 0.8.3 as the most recent, but when I checked CRAN's sources list there was 0.8.7, which I then installed. Do I really need to uninstall it and then reinstall, as described above?

Edit: I uninstalled and reinstalled, and I still have the faded color problem with the exact same code quoted in the original post.