Revisions allow you to track differences between multiple versions of your content, and revert back to older versions.
Variations include:
Error in single.na(to) : argument is missing, with no default
Typical cause: A leading or trailing comma in your code makes R think that you wanted to pass in a parameter, but left it empty (hence "missing, with not default")
Examples:
leading comma
to=c(,'x','y','z')
trailing comma
mxMatrix("Name"
nrow=3,ncol=3,free=TRUE, values=.5,
)
Cure: remove the errant comma