Not sure what you mean by “wordpress test environment”. Are you referring to wordpress default theme or on a different set up with exactly the same plugins and theme as on your live site. Since this works on our demo site http://demowp.webtechideas.com/, we are unsure what’s wrong at your end.
We need to have a look at a live site to know the issue and suggest you with ant fix. Can you please set up a demo site with exactly the same set up? Also please provide admin access of the demo site so that we can investigate the issue.
I mean a wordpress test intallation on my pc. there is all fine with our template and your plugin. With the standard wordpress theme ‘twentyfourteen’ online it works also, but not with our own template online.
For testing, i can give you a access to our site, then you can look in realtime.
please contact me through email, so that i can give you login.