Dim or blend frame window when inactive.

Hello - I've been researching this all day without any luck. I have a multi-top-level interface application with several open frame windows. When the user is taking some action on one frame window, I'd like the other frame windows to dim so it's clear that the user is operating on the given window. Visual Studio 2010 does this sometimes when its thinking (or crashed) - the entire VS window is blended with a white. Here's a screenshot of an example:

http://www.telerik.com/ClientsFiles/314561_Crash.png

Here is another example:

http://www.addictivetips.com/windows...-with-ghoster/

But I only want to dim other windows in my application, not the entire desktop. I looked into using layered windows and UpdateLayeredWindow, but if that's the answer, I'm not using it right. Does anyone have suggetsions? Thanks in advance!

- Steve