There is an option in the user interface dialog dialogClasswhere you can specify the css classes that are added to the dialog style. This way you can define a class, for example:
.dialogFixed {
position: fixed !important;
}
and call the dialog box like:
$(function() {
$( "#dialog" ).dialog({
dialogClass: 'dialogFixed'
});
});
A fixedposition should fit your requirements here.
Demo : http://jsfiddle.net/MpHN9/
(, css , , . , )