DIV mask layer not fully covered on top when there is a scroll bar

It's common to create a "mask" layer on top of the page in order to display photos, pop-up messages, etc.

I used to use the "absolute" positioning to do the job under I lately discovered the so called "masked" will move if there is a scroll bar (when shrinking the window's size).

This problem can be easily solved by just setting the DIV to "fixed" position.

Another problem solved! But wait a minute. This solution doesn't work in IE! Let me see if there is a workaround for this...