This is a really cool new feature in Visual Studio 2008 that allows you to debug into framework code, all you have to do is follow a few simple steps.

1. Start Visual Studio and select Tools -> Options

2. In the options dialog select Debugging -> General

3. There are two settings you need to change in here. Firstly ensure the “Enable Just My Code (Managed only)” tick box is NOT selected.

4. Secondly ensure that the “Enable source server support” IS selected.

5. Still in the options dialog box select Debugging -> Symbols, here you need to tell Visual Studio where it can find the pdb files and where it should store these on your computer.



6. Click the new location button and specify the URL http://referencesource.microsoft.com/symbols as the symbol location and select a location on your computer where the pdb files will be cached by clicking the "Browse" button.

Now you can debug into the .NET framework code as you need. You can watch a video on how to do this by Daniel Moth on Channel9, or checkout Shawn Burke’s Blog.