Error "[Line:0 Position:0]

Jun 7, 2012 at 12:47 PM

Hi, I'm creating an app for SL5 (VS2010), and after getting several groupboxs on a page, I now get the following error as soon as I add the child control (StackPanel) to the groupbox:

NullReferenceException was thrown on GroupBox34343: [Line:0 Position:0]

Object reference not set to an instance of an object.
   at SilverlightContrib.Controls.GroupBox.OnApplyTemplate()
   at System.Windows.FrameworkElement.OnApplyTemplate(IntPtr nativeTarget)
Anyone seen this error? Thanks for any suggestions.