I sat down today to work on a website. I have about 30 e-commerce products to add and a lot of work ahead of me. To my surprise, I discovered that the product lightbox was being rendered below the fold, Instead of centered vertically. The pop-up product images were working just fine a couple of days ago.
Oh no the gremlins again.
So after nearly half a day of trying to figure out what re-programming of mine cause this. I discovered the culprit.
jQuery - FU
My theme currently loads the latest version of jQuery from Google. I was using the 'load latest version 1.XXX' URL syntax: http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js
So the latest jQuery update, just like the rest of them is not backwards compatible. Am tired of returning to broken sliders, lightboxes and the like. This particular breakage was in the lightbox that Marketpress uses by default, Lumebox.
Looks like https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js works with Marketpress. The 1.xxx load must have loaded a newer version that breaks MP.