We have a large amount of data to be processed and brought over from the backend. While this is happening, I would like to show a a large spinning wheel throbber (http://en.wikipedia.org/wiki/Throbber#Spinning_wheel) overlay the application window.

How do I achieve this? Ideally I want to have the overlaying throbber still show the application window in the background, kind of in a translucent mode that I have seen elsewhere