show() Me the Way to Go Home (IDLE/Win)

Note the show() on the last line below. If I run this program from IDLE, it displays the graph, and sits there. I would like to finish, by getting to an active shell script. If I close the figure using x in the upper right, it disappears. Now two windows are seen. The code and script window. The script window is not active. I can't enter anything into it. The cursor is below the >>>. Ctrl-C doesn't work. If I use the x in the upper corner, eventually the script window disappears. How do I just return to the script? There ought to be a smooth way to do this by putting something after show().

import matplotlib
from pylab import figure, show
import numpy as np

# make an agg figure
fig = figure()
ax = fig.add_subplot(111)
ax.set_title('a simple figure')


My life in two words. "Interrupted Projects." -- WTW (quote originator)