I just installed it on v3.8.6 and it works fine. As has been said, to test it you need to send a PM to another account not your own. I could not figure out how to change the colors, but I did edit the
product-gtpm_popup.xml file from:
Code:
...border="0" width="100%" align="center">
to
Code:
...border="0" width="50%" align="center">
and then re-imported the product w/overwrite=ON
That helps make it somewhat more noticeable, for users since it's not the same WIDTH as the rest of the page.