Weird div lag in overlay

[rigidkitchen]

I set up shadowbox to work with a newly-configured dynamic gallery output with NextGen Gallery (Wordpress)

However, when loading and browsing through images while using shadowbox, the gallery div 'pokes through' the overlay and does otherwise kooky stuff if the shadowbox image viewer is placed over the gallery underneath.  Is this an issue with my div structure?  It's about 6 divs deep, and every image is in it's own div.  



Please see here: http://rigidkitchen.net/archives/happy-holidays

I have also set up overlay navigation icons (like lightbox), if anyone would like the code for that just let me know through this forum, I'd be happy to post it.  

To give credit, thank you to the web developers at Arc'teryx - I used their site as an example