I got bitten by another bug, a minor one.
I need some fancybox plugin for NextGEN gallery, and for this I use the easy fancybox plugin.
For it not to conflict with the fancybox included in your plugin, I'm using slimbox to display galleries on the worldmap: it works fine.
There is however a small glitch: if I activate overlays in easy fancybox, the overlay gets on top of any images of the site, getting them grey, except on the worldmap. Click on any picture here for an example:
I reported the problem on easy fancybox's forum, and this plugin's dev (RavanH) pointed a conflict on stylesheets from his and your fancybox. Link here:
As I said, it's a minor problem, as I can disable overlays for pictures not on the worldmap.