Silverlight: Xaml Blend Namespace Error Not Resolved

XAML Namespace http://schemas.microsoft.com/expression/blend/2008 is not resolved. This error can occur when certain Xaml elements added by blend have not been properly ignored during non design/debug situations and Blend or Visual Studio reports such error. To resolve the error one must add the mc:Ignorable attribute to the namespace declarations to inform the Xaml compiler to ignore a specific