Mike is right. You need a call to drawnow in your listener. In this case you are asking for 5000 scans per second. That is faster than eye can observe so you'll want to limit the drawnow rate. Drawnow has an option called "limitrate" for this purpose.
If you call "drawnow limitrate" in your listener you'll get the plot updates.
You might also benefit from the "nocallbacks" option in this case. Try it out and let me know.