Make fancybox appear on top
Fancybox has it's own CSS file, and you should look for #fancybox-wrap
and change it's z-index'es there. But anyways, it has pretty high setting by default (1101 on mine), therefore I'd suggest altering your own HTML/CSS.
Just in case, check if you have added that fancybox stylesheet in your HTML.
I've addded:
.fancybox-overlay {
z-index: 1000000 !important;
}
in my stylesheet for recent version of fancybox.