WPF: Microsoft_Windows_Themes not found

I am getting this error in my WPF app:

The type 'Microsoft_Windows_Themes:ScrollChrome' was not found. Verify that you are not missing an assembly reference and th开发者_运维知识库at all referenced assemblies have been built.

Any idea?

Make sure you add this reference in the top most tag of your control/page/resource dictionary/whatever:

...

xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero">

And add a reference to PresentationFramework.Aero in your project.