[R-SIG-Mac] Screen device under macOS X

[John Maindonald]

When I start up R (or at least 64-bit R) from the command line
or from ESS, and plot a graph without first opening a graphics
screen window, I get an X11 window.  

If I type capabilities(), I get:

> capabilities()
    jpeg      png     tiff    tcltk      X11     aqua http/ftp  sockets 
    TRUE     TRUE     TRUE     TRUE     TRUE     TRUE     TRUE     TRUE 
  libxml     fifo   cledit    iconv      NLS  profmem    cairo 
    TRUE     TRUE    FALSE     TRUE     TRUE     TRUE     TRUE 

Given that "aqua" is available, why do I not get a quartz window? 
(I can of course open such a window.)

> sessionInfo()
R version 2.13.2 (2011-09-30)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

locale:
[1] C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] lattice_0.19-33

loaded via a namespace (and not attached):
[1] grid_2.13.2  tools_2.13.2

John Maindonald             email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.
http://www.maths.anu.edu.au/~johnm