I am playing with the IoC Container Unity, and according to the documentation, adding this xmlns attribute to the "unity" section must allow Visual Studio doing some Intellisense stuff :
<configuration>
    <configSections>
        <section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection, Microsoft.Practices.Unity.Configuration"/>
    </configSections>
    [..]
    <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
        [..]
    </unity>
</configuration>
Actually, it doesn't work. It seems the resource has been (re?)moved. Do you know the new link ?