mplh5canvas backend over ssh tunnel

I have the HTML5 Canvas backend working on an Ubuntu machine using
the latest EPD distribution.

However, I am unable to get it to work through an ssh tunnel.

- I create a tunnel forwarding port 9000 on the Ubuntu host machine
through a firewall machine to port 9000 on my local client.
- I run examples/ in a separate ssh-tunneled terminal
- I open in Google Chrome on the client.

I get the HTML 5 Canvas window, but no plot appears and it says
'Disconnected'. Same thing happens if I open a browser in a Gnome
session on the host. Running the example on the host in a Gnome
session and viewing from a client does not work either.

But running the same example from a terminal on the host _and_ viewing it in a
Gnome session on the host works.

When I run the example, it tries to open a terminal based browser like
lynx and w3m. I uninstalled these applications and now get nothing, but
this may be an issue. On the host, it opens the window in Chrome automatically
and starts the browser if necessary. Is there a way to stop this behavior?