GGally - unexpected behavior with ggpairs(…, diag = list( continuous = 'density'))

Question

I am trying to generate a scatterplot matrix with density plots in the diagonals (using ggplot, preferably). The documentation for ggpairs in the GGally package sta

Answer 1

So I finally figured this out, by studying a different question here. It turns out that unless axisLabels is set to "show", density plots on the diagonal are suppressed, without warning.

xx <- mtcars[,c(1,3,4,6)]   ## extract mpg, disp, hp, and wt from mtcars
library(GGally)
ggpairs(xx, diag=list(continuous="density"), axisLabels='show')

Produces this, as expected: