PixiEditor/PixiEditorDotNetCore3/App.xaml

<Application x:Class="PixiEditor.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:PixiEditor"
             StartupUri="Views/MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Styles/MenuButtonStyle.xaml"/>
                <ResourceDictionary Source="Styles/ThemeStyle.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>