In a past post I mention how to enable Help Viewer Messages for help debugging.
Here's how to enable help debugging in VS 2010.
In this snippet of a VS Help Integrators Yahoo Group post, Paul O'Rear [MSFT] mentions a way to switch Help debugging on in Visual Studio 2010.
Add registry item
After a restart VS 2010 now has a new Help menu item.
Click "Debug Help Context" to show the window.
The content is dynamic. Here you can see that as soon as I select "WebServices" or click it, the help context has changed and the Debug window immediately shows the Help context info.