In your css folder open the admin.css file and look for the class name:
.light_box and you should see the property:
position:absolute;
change it to:
position:fixed;
This should give you the result you are looking for.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.