[R-SIG-Mac] R.app GUI under El Capitan: No response or "CGContextGetCTM: invalid context 0x0"

[Steph Peacock]

I have also been having this problem when saving plots for months -
extremely frustrating. Seems to freeze regularly, especially if I try to
navigate to a different folder when saving. 

I seem to get the same lack of response sometimes when saving a workspace
file.  This occurs almost every time if I select Workspace -> Save
Workspace, and on occasion when using the command line save.image(). Was any
solution found? 

See also
http://r.789695.n4.nabble.com/R-G-GUI-freezes-saving-plot-td4718731.html 

Happy to provide details on request.