[R-SIG-Mac] select text in R console and editor

[Tiago R Magalhaes]

Hi

sometimes when trying to select text with the mouse in either the R 
console or an editor script, there's no way to do it. It's still 
possible to select in some other areas, but in others it isn't. 
Noting that important, but it has happened once in a while.

I also get the undo key "extreme" behaviour mentioned in an earlier 
posting. And that's scary!

thanks to all the people that have done this wonderful work.