Filled boxplot with constrained y-axis fills box only partially

[TillF]

A boxplot with constrained y-axis fills the box only partially.

do_plot = function() #do a boxplot with constrained y-axis
{
  boxplot(testdata, ylim=c(0.4, 2), col="grey")
}

#create test data
set.seed(seed = 1)
testdata = runif(n = 10)

do_plot() #this is how it should look
  
library( ReporteRs )
unlink("test.pptx")
mydoc <- pptx()
mydoc = addSlide( mydoc, slide.layout = "Title and Content")
mydoc <- addPlot( doc = mydoc, fun = do_plot, vector.graphic=TRUE)
writeDoc( mydoc, file = paste0("test.pptx"))  #this creates a box which is only filled with grey above and right of the diagonal

sessionInfo()
R version 3.3.2 (2016-10-31)
Platform: i386-w64-mingw32/i386 (32-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

locale:
[1] LC_COLLATE=German_Germany.1252 LC_CTYPE=German_Germany.1252
[3] LC_MONETARY=German_Germany.1252 LC_NUMERIC=C
[5] LC_TIME=German_Germany.1252

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

other attached packages:
[1] gdtools_0.1.6 ReporteRs_0.8.9 ReporteRsjars_0.0.3
[4] magic_1.5-6 abind_1.4-5 berryFunctions_1.15.0
[7] rJava_0.9-8

loaded via a namespace (and not attached):
[1] Rcpp_0.12.15 knitr_1.15.1 xml2_1.1.1 magrittr_1.5
[5] uuid_0.1-2 xtable_1.8-2 R6_2.2.0 tools_3.3.2
[9] rvg_0.1.8 R.oo_1.21.0 png_0.1-7 htmltools_0.3.6
[13] digest_0.6.12 zip_1.0.0 shiny_1.0.3 officer_0.2.1
[17] base64enc_0.1-3 R.utils_2.6.0 mime_0.5 R.methodsS3_1.7.1
[21] httpuv_1.3.3