zen cart 1.3.9.d upgraded from 1.3.8a

I received a notice from a customer that my lightbox (zen lightbox 1.5) was hanging in their google chrome browser when they clicked on a product picture. I checked it with my google chrome and sure enough it was hanging in mine too. I removed the lightbox and tried different versions with no luck so I went back to my original zen lightbox and now that won't work right.

I had it installed on zen 1.3.8a working good and carried it over during update to zen 1.3.9d but now that's it has been removed and trying to put it back it just won't work right in any browser. I click on an image and I can see the lightbox trying to open and then the image just pops out opening in the browser instead and then I have to click the browser back button to go back to my store.

I tried aozhaver's fix but it didn't make any difference to what is happening.

There are no debug files in my cache for a clue.