[R-sig-eco] extent of graphic image in graph pane

[Michael Marsh]

I've been using mvpart with graphic output (a tree displaying env. data 
governing splits), augmented by rpart.pca, to explore environmental 
relations of vegetation data on my old Toshiba satellite computer with R 
version 2.15.0 (x32).
I've loaded R version 3.3.3 (x64) on a Surface Book.
Graphic images on the old computer appeared to extend to the limits of 
the graphic pane, but with the identical script in R 3.3.3, they are 
confined to the upper left corner of the pane as if the pane was ready 
to accept 3 more images of the same size. This makes it difficult to 
copy and paste a usable sized image into a Word document
I have searched the graphics chapter of R-Intro without success.