SilverLight 4 Debugging Query

I have created a simple application in VS.NET 2010 for SilverLight 4.
I have the following error :

Microsoft Visual Studio

Unable to start debugging. The application uses a version of Silverlight that is not supported by the debugger.



I have changed the version From
<param name=“minRuntimeVersion” value=“4.0.50401.0” />
to :
<param name=“minRuntimeVersion” value=“4.0.50524.0” />
for test.
But it did not work.

Can anyone tell me what I should do?


It is already installed.


Might be a stupid question, but did you install SL 4 Tools for VS? As VS2010 comes bundled with SL 3, and not 4.