My (Un)Modal Popup

I have added a modal popup to my user control. I show the modal popup by registering a startup script in the code-behind of an update panel trigger. The modal popup appears, but it isn't modal. I can click and edit the form fields behind the modal popup. Has anyone seen this happen? Any thoughts on how to fix it?Post code and I might be able to help you

Have you set the BackgroundCSSClass properly? I saw the same behavior and was able to fix it by setting the BackgroundCSS... here's an example of the CSS I used

.modalBackground

{background-color:Gray;filter:alpha(opacity=70);

}

I used below css but still my main page controls can be accessed?

.modalBackground

{background-color:Gray;filter:alpha(opacity=70);

}

This is happening in (Un)Modal fashion, any have solution for this.