Silverlight page goes blank when style is in another file

I've styled a Silverlight DataGrid control and when the style is in UserControl.Resources, it applied to the DataGrid correctly. But If I move it to a Styles.xaml file and add the following to App.xaml,

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Themes/GridStyle.xaml" />
            <ResourceDictionary Source="Themes/Styles.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

The page just goes blank after loading and I get the "Error" Icon in the browser status bar.

This is not something to do with the style file not being loaded because several other styles from the 'St开发者_开发问答yles.xaml' file apply correctly. Only one style causes this error.

Note: The Style has an element with a binding to the viewmodel which is defined in UserControl.DataContext. Could this have something to do with it?

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Try

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="/[Project name];component/Themes/GridStyle.xaml"/>
            <ResourceDictionary Source="/[Project name];component/Themes/Styles.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>