ModernWpfPlayground/App.xaml

<Application
    x:Class="ModernWpfPlayground.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:ModernWpfPlayground"
    xmlns:ui="http://schemas.modernwpf.com/2019"
    StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <!--<ResourceDictionary>
                    <Style
                        x:Key="TextBoxStyle"
                        BasedOn="{StaticResource {x:Type TextBox}}"
                        TargetType="TextBox">
                        <Style.Triggers>
                            <Trigger Property="IsReadOnly" Value="True">
                                <Setter Property="Background" Value="WhiteSmoke" />
                            </Trigger>
                        </Style.Triggers>
                    </Style>
                    <Style BasedOn="{StaticResource TextBoxStyle}" TargetType="TextBox" />
                    <Style BasedOn="{StaticResource TextBoxStyle}" TargetType="propertyPresenter2:TextBoxEx" />

                </ResourceDictionary>-->
                <local:IntellisenseResourceDictionary Source="/ModernWpf;component/DesignTime/DesignTimeResources.xaml" />
                <ui:ThemeResources />
                <ui:XamlControlsResources />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>