IDL>
window ; open
a window
IDL> window,2 ; open another
window, indexed 2
IDL> window,3,xsize=150,ysize=150 ; open a 3rd window
IDL> wshow,0 ; bring
window 0 in front
IDL>
wset,2
; set focus to window 2
IDL> wdelete,2 ; delete
window 2
if no window is open at the first call of s a plotting routine,
it will open windows_0.
