Need help printing from within XUL environment

I have a very simple XUL environment set up that displays a link in an iframe that should bring up the print dialog box when clicked. The problem is that nothing happens when it's clicked. I'm not very familiar with XUL and can use some help getting this to work... Thanks! Ok, here's the simplest way I can come up with to reproduce the issue. Step 1: Download Ubuntu Xenial Server 16.04.3 LTS and install with user 'kiosk'. Step 2: Log in as 'kiosk' user and update apt-get update. Step 3: Install following packages: apt-get install xorg compiz compizconfig-settings-manager compiz-plugins compiz-plugins-default apache2 firefox. Step 4: Download the attached '[login to view URL]' file and unzip in the same folders that are in the archive. Step 5: Run the following commands: systemctl set-default [login to view URL] rm -Rf /var/www/*.html rm -Rf /var/www/html chown -R www-data:www-data /var/www/ Final Step: Reboot - If all goes well, you should see a white screen with a link in black letters that reads 'Click here to print.'