[Rd] possible bug in grid

[Deepayan Sarkar]

Hi,

?gpar says:

     Specifying the value 'NULL' for a parameter is the same as not
     specifying any value for that parameter, except for 'col' and
     'fill', where 'NULL' indicates not to draw a border or not to fill
     an area (respectively).

However, I get

> library(grid)
> grid.points(gp = gpar(font = 1)) # works fine
> grid.points(gp = gpar(font = 1, fontface = NULL))
Error in validGP(list(...)) : Must specify only one of 'font' and 'fontface'

This happens in 2.3.1 as well as r-devel.

Deepayan