Atlas: ModalUpdateProgress - An UpdateProgress Control in Modal Popup Style
ASP.NET AJAX has a cool UpdateProgress control
that provides a visual indicator while one or more of the
UpdatePanel controls are being updated.
However, it will be much more useful if all other elements
on the page could be disabled when the
UpdateProgress is shown. This led Ting Huang to
build the ModalUpdateProgress control in which
the UpdateProgress will act as a modal popup.