Thomas, any chance that you could have problems with your graphic driver? For instance, if you have an Nvidia graphic card, I would recommend switching from the 'nouveau' driver to the official Nvidia one.
Kind regards, luca [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.