Style not applied at runtime in NF 4.5

I have a set of nested styles that are referenced within a MergedDictionary in App.XAML. The styles are applied correctly at design-time, but aren't applied at runtime.

I'm aware of the 4.0 optimization bug described here, but the recommended solution of adding a dummy default style directly in app.xaml isn't working in 4.5.

Any suggestions?

Rebecca M. Riordan