I think it would also be a good idea to make it clear that the code on that documentation page:
<Application x:Class="SampleApplication.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:app="clr-namespace:SampleApplication;assembly=SampleApplication.SL">
<Application.Resources>
<app:AppBootstrapper x:Key="Bootstrapper" />
</Application.Resources>
</Application>
I don't think it will work for a WPF app, you've got to use:
<Application x:Class="SampleApplication.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:app="clr-namespace:SampleApplication;assembly=SampleApplication.SL">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary>
<app:AppBootstrapper x:Key="Bootstrapper" />
</ResourceDictionary>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>