Nyromodal squishes the background when in a modal window

Question

Nyromodal is disrupting the background whenever a link is pressed to open a modal window. If you press 'about me' on http://imdarrien.com/ (it seems to be need to be pressed twice for the problem to show) you'll see what I mean. I've tried playing with the nyroModalBg css but can't seem to get it right.

.nyroModalBg {
position: fixed;
overflow: hidden;
top: 0;
left: 0;
height: 100% ;
width: 100% ;
opacity: 0;