Error in the designer

[ADM-IT Denis Pujdak]

<ScrollViewer Grid.Row="1" VerticalScrollBarVisibility="Auto" Background="White">
            <telerik:RadBusyIndicator IsIndeterminate="True" IsBusy="{Binding IsBusy}" BusyContent="{Binding BusyMessage}">
                <StackPanel Orientation="Vertical" Style="{StaticResource EditAddMainStackPanelStyle}">

Visual Studio 2010 SP1
Silverlight v. 5.0.5.0
Telerik v. 2012.2.725.1050

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System.InvalidOperationException
Layout measurement override of element 'Microsoft.Windows.Design.Platform.SilverlightViewProducer+SilverlightContentHost' should not return PositiveInfinity as its DesiredSize, even if Infinity is passed in as available size.
   at System.Windows.UIElement.Measure(Size availableSize)
   at System.Windows.ContextLayoutManager.UpdateLayout()
   at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
   at System.Windows.Media.MediaContext.InvokeOnRenderCallback.DoWork()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
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System.Windows.Markup.XamlParseException
 [Line: 0 Position: 0]
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at MS.Internal.XcpImports.UIElement_Measure(UIElement element, Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at System.Windows.Controls.ScrollContentPresenter.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)

Microsoft.Windows.Design.Platform.InvalidDesignerUpdateException
An unhandled exception was encountered while trying to render the current silverlight project on the design surface. To diagnose this failure, please try to run the project in a regular browser using the silverlight developer runtime.

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InvalidOperationException was thrown on "RadBusyIndicator": [Control_TargetTypeMismatch]
[Control_TargetTypeMismatch]
Arguments: 
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=5.1.10411.0&File=System.Windows.dll&Key=Control_TargetTypeMismatch
   at System.Windows.Controls.Control.ApplyTemplate()
   at Microsoft.Expression.Platform.Silverlight.InstanceBuilders.SilverlightViewNodeManager.EnsureElementInDictionary(Object root, ViewNode knownAncestor)