Hi,
I've noticed a bunch of people on the forum with display of the overlay/shadowbox on iOS devices. I finally found the css line that Vaska was talking about for anybody that is interested:
You can fix this at /ndxzsite/css/overlay.css
From Vaska:
Around line 25 replace the #dialog rule with this one (we're simply adding a missing z-index):
#dialog { position: fixed; top: 0; left: 0; text-align: left; width: 100%; padding: 0; margin: 0; z-index: 4; }
Worked for me.