Problem adding Telerik.Windows.Controls.GridView.dll to Toolbox

[Chris]

I'm trying to add the Grid component to my toolbox and I get this error:

Could not load type 'System.ComponentModel.GroupDescription' from assembly 'System.Windows, Version = 2.0.5.0, Culture=neutral,PublicKeyToken=7cec85d7bea7798e'.

I have the latest internal build of the SilverLight 3 Rad Controls.

[Boyan]

Hi Chris,

This error is usually given when you are trying to add Silverlight component not in the Silverlight Components Tab. Be sure that you have selected the Silverlight Components Tab. You can check this KB article.

Regards,
Boyan
the Telerik team

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[Robert]

I am also encountering the same error when trying to add the Grid component to my toolbox.
1. Selected Tab "Telerik Silverlight 2"
2. Right clicked inside of the tab, from the menu clicked Choose Items
3. Clicked the Silverlight Components tab, click Browse 
    browsed to path, C:\Program Files\Telerik\RadControls for Silverlight Q2 2009\Binaries\Silverlight
4. Selected Telerik.Windows.Controls.GridView.dll
5. Clicked Open

Could not load type 'System.ComponentModel.GroupDescription' from assembly 'System.Windows, Version = 2.0.5.0, Culture=neutral,PublicKeyToken=7cec85d7bea7798e'.

[Vlad]

Hi Robert,

You are trying to add Silverlight 3 binary - do you have Silverlight 3 installed?

Kind regards,
Vlad
the Telerik team

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[Robert]

yes, I have Microsoft Silverlight 3.0.40818.0 installed

[Robert]

I was able to add the GridView control to the Toolbox after installing the Microsoft Siverlight 3 Tools for Visual Studio 2008 SP1. The "Getting started with Silverlight" documentation does not state to install Microsoft Siverlight 3 Tools.