!P.Region
Specifies the positioning of the plot and its associated annotation (i.e., anything that can be specified with the PLOT command). The difference between !P.Region and !P.Position is that !P.Region provides a margin around the plot to accommodate plot annotation. It is called by specifying !P.Region’s maximum and minimum values in normalized coordinates:
!P.Region = [Xmin, Ymin, Xmax, Ymax]
For example, to position a plot with its associated annotation in the center of the screen, type:
!P.Region = [0.2, 0.2, 0.8, 0.8]