def show():
for manager in Gcf.get_all_fig_managers():<EOL><INDENT>manager.show()<EOL><DEDENT>if show._needmain:<EOL><INDENT>Fltk.Fl.run()<EOL>show._needmain = False<EOL><DEDENT>
Show all the figures and enter the fltk mainloop

This should be the last line of your script