[Rd] text(1:10, col=NA) is not transparent

[Peter Ruckdeschel]

Maybe I am missing something, but according to the help page
to par (section "Color Specification"), which is referred to in the
help to text argument col:

‘"transparent"’ or (integer) ‘NA’ is _transparent_,
useful for filled areas (such as the background!), and just
invisible for things like lines or text.

but:

col0 <- as.integer(NA)
is.integer(col0)
### is this coercing to "integer" necessary?
plot(1:10)
text(1:10, col=col0)
### text is plotted

##whereas
plot(1:10)
text(1:10, col="transparent")
### text is not plotted

# Of course, this is not terribly urgent, as a color value of 0 also
plot(1:10)
text(1:10, col=0)
### text is not plotted

Best, Peter