Jquery popup background grayed out for very lengthy pages (for height more than 65536px)

[aslamr]

I attached a sample HTML file with the CSS using jsFiddle. Please use this link: ​http://jsfiddle.net/KTXdg/ to open it and follow these steps.

In the html file, there are two types of overlays, one is the overlay that is created using regular, old CSS. When the link to show that CSS overlay is clicked, the overlay that's shown is semi-transparent like it's supposed to be. However, when the link to create the jQueryUI modal dialog is clicked, the background overlay is completely opaque. This only occurs after the size of the document is a certain size (65536). To test this, with the 'main' div, when the height is at 65520, this issue is occurring. As soon as that's moved down to 65519, then the issue is not there

[Scott González]

Duplicate of #6801.