At present the powder diffractogram viewer modul only allows viewing. Printing capabilities will be implemented in future versions of JSV.
You may select an area by dragging a selection rectangle. Once you are in that zoom mode you may drag the pattern to the left/right by mouse drags. Double clicking on the display area or clicking the button "full pattern" will return to the full pattern display.
The same holds for the IGOR file viewer. Only there you have extra options to switch Fc, Fo, Fdiff and Bragg ticks on/off.