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