Fancybox iFrame modal : How can I avoid its resizing when I reduce the size of the browser window?

I have created a modal based on an iframe, using Fancybox. It's for a login box. But whenever I reduce the size of the browser window, the fancybox reduces itself as well and I cannot control it. I have set the size of width and height of thi开发者_如何学运维s fancybox, but it keeps resizing when I Reduce the size of the browser window. How can I stop that behavior ? Thanks.

Set autoscale & autoDimensions to false

http://fancybox.net/api