I can’t replicate the issue. Make sure that you have the latest Deducer/ggplot2. There have been some recent changes to ggplot2 that may be causing your issue. Your sessionInfo should look something like:
> sessionInfo()
R version 3.2.2 (2015-08-14)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.11.2 (El Capitan)
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] Deducer_0.7-9 MASS_7.3-43 car_2.1-0 ggplot2_2.0.0 JGR_1.7-16 iplots_1.1-7 JavaGD_0.6-1
[8] rJava_0.9-7