Attribute image swap - works for one option, but not another

I've inherited this project from a developer who did some sneaky stuff behind the scenes. But I'm hoping someone here can shed some light on what might be happening:

We have an option of "color" with dropdown options.

When product attributes are created from this option, the image swatch will swap in place of the main product image. At the same time, the correct attribute will be changed in the dropdown menu.

Everything works great.

So I created a new dropdown option and created attributes the same way. But while the thumbnails will swap into the main product image, the dropdown menu is not affected.

I've compared the two sets of attributes and everything appears to be identical. Any ideas what might be happening?

Thanks,

John

Image swap is not builtin but a 3rd party plugin contributed

You might review that area

Thanks. I looked in plugins and didn't find anything that seems to match what I find on the product display template. The portion that appears to be making the attribute image swap has this function:

function product(id, option, img2swp)

any idea what plugin or function that might be referring to?

Could be this one???
http://www.zen-cart.com/downloads.php?do=file&id=564

Bummer no. It looked close, but there are no Ajax files and I didn't see any reference to any on the template pages. Thanks for the suggestion, though.

I noticed a jquery file in there, so I'm thinking it might be custom job.

John