Can't figure out why I get Error loading static resource from app.xaml

Question

I having trouble getting my ResourceDictionary.MergedDictionaries to load from app.xaml.

My WPF app has a static class with a Main defined and startup object set to it. Within Main I created an instance of App and run it. The override OnStartup fires and the mainwindow.cs InitializeComponent gives the error "Message "Cannot find resource named 'MaterialDesignFloatingActionMiniAccentButton'. If I put the resources in the mainwindow.xaml everything is fine, but I wanted them to load at the app level so I they are not in each page. Any help appreciated.

public partial class App
{
    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);
        var app = new MainWindow();
        var context = new MainWindowViewModel();
        app.DataContext = context;
        app.Show();
    }
}

from the Main..

       var app = new App();
       app.Run();

app.xaml..

<Application x:Class="GS.Server.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Dark.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Primary/MaterialDesignColor.Grey.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Accent/MaterialDesignColor.Red.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>