leyenda aguado ggplot2

Question

estoy tratando de utilizar el nuevo sistema de guías en ggplot2:

require(devtools)  
dev_mode() 
install_github("ggplot2") 
require(ggplot2) 

require(reshape2) 
p <- ggplot(melt(outer(1:4, 1:4)), aes(x=Var1, y=Var2)) + geom_tile(aes(fill=value)) 
p + guides(fill = guide_colorbar()) 

Sin embargo la leyenda se ve una especie de washy (no como todos los otros ejemplos que he visto):

¿Qué estoy haciendo mal?

> sessionInfo() 
R version 2.14.1 (2011-12-22) 
Platform: x86_64-pc-linux-gnu (64-bit) 

locale: 
[1] LC_CTYPE=en_US.UTF-8  LC_NUMERIC=C    LC_TIME=en_GB.UTF-8  LC_COLLATE=en_US.UTF-8  
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 LC_PAPER=C     LC_NAME=C     
[9] LC_ADDRESS=C    LC_TELEPHONE=C    LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C  

attached base packages: 
[1] grid  stats  graphics grDevices utils  datasets methods base  

other attached packages: 
[1] reshape2_1.2.1 ggplot2_0.9.0 devtools_0.6 gridSVG_0.8-1 proto_0.3-9.2 rgeos_0.2-3  stringr_0.6  gpclib_1.5-1 
[9] maptools_0.8-14 lattice_0.20-0 sp_0.9-95  foreign_0.8-49 

loaded via a namespace (and not attached): 
[1] colorspace_1.1-1 dichromat_1.2-4 digest_0.5.1  MASS_7.3-17  memoise_0.1  munsell_0.3  
[7] plyr_1.7.1   RColorBrewer_1.0-5 RCurl_1.91-1  scales_0.2.0  tools_2.14.1 

Answer 1

se ve bien con la versión estable de CRAN ggplot2_0.9.0 y reshape2_1.2.1 Tal vez podría informar del fallo here.