prog define diffplot_viewgph
*!	Called by -diffplot.sthlp-
	version 11
	local gphset `c(graphics)'
	if "`c(graphics)'"=="off" {
		cap noi set graphics on
	}

	local plus : sysdir PLUS
	if "`1'"=="" {
		local 1 1
	}
	graph use `"`plus'_/__diffplot_ex_`1'.gph"'

*	set graphics `gphset'
end