Improving the Start-up Performance of the WPF and Silverlight Designer in Visual Studio 2010 Beta 2

I wanted to let you know about a last minute change that went into VS 2010 Beta 2 that you can use to improve the startup performance for the WPF and Silverlight Designer.  The change went in late and it was a little risky, so we decided to leave it off until we had a chance to do some more testing with it.  You can turn the change on yourself via a registry key.  We expect the change will be on all the time in the final product, so changing the registry key is strictly a Beta 2 issue.

You can read more about it here:

If you have any feedback on how this works (or doesn’t work) for you, please let me know.  You can contact me at




Comments (2)

  1. Justin_H says:

    Neither your summary nor the linked note actually says what this does other than "improves performance." Can you please tell us a little about what this actually does?



  2. David Berg says:

    The WPF and Silverlight designer uses multiple domains to isolate the work being designed from Visual Studio.   This flag setting changes VS hosts the CLR so that it manages and shares information across multiple domains in a way that enables new domains to load faster.  (VS is a native app that hosts the CLR, not a managed app loaded by the CLR.  The distiction allows us more control over the CLR than a typical application has or needs.)