In case anyone ever wonders if Microsoft produces any real apps (other than Microsoft Max) using managed code, here you go:

Expression Interactive Designer (aka Sparkle) is a 100% .NET, managed code application.  The source is currently more than 1200 .cs files and about 140 .xaml files totally 210,000 some lines of C# and 23,000 some lines of XAML.  There is no unmanaged code directly in the Sparkle source, and only one PInvoke.  The single PInvoke is used to call out to HtmlHelp.  We could have used the managed wrapper for HtmlHelp, but that is in the WinForms assemblies, and since we are so Avalon based we decided to avoid additional WinForms dependencies (frankly, for interop reasons we will probably have them anyway, but sometimes it is the thought that counts).

Read more on John Grossman's Blog

Also check out John's History of Sparkle.

... Most importantly, I think the message is compelling:  you could not build Director in Director, Flash in Flash, FrontPage in HTML.  But we built Sparkle using the Avalon runtime it targets, and in fact much of the UI of Sparkle was developed using Sparkle (the internals are still built using VS...we still believe high-end developers will gravitate to that tool)...