Sergey Barskiy encountered a small problem with his new project and
Blend but luckily managed to find a solution.
Source: Sergey Barskiy's Blog
I can use styles from MyResourceDictionary.xaml, but Blend generates an error for me – it cannot find my resources. Here is an easy way to overcome this issue. You have to add the same dictionary into the resources of each screen: In the example below I am showing resources area for a user control called MySampleView from MyApp module.