C# WPFLocalizeExtension only showing default Strings.resx

Question

I tried using WPFLocalizeExtension and only the default Strings.resx and sometimes the last modified one is shown. Please help me to get back on track! I will attach a .zip of my folder. Thank you for your time!

App.xaml.cs =

public partial class App : Application
{
public App()
{
    LocalizeDictionary.Instance.Culture = CultureInfo.CurrentCulture;
}

}

XAML =

<Window x:Class="WPF_Localization.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800"

        xmlns:lex="http://wpflocalizeextension.codeplex.com"

        lex:LocalizeDictionary.DesignCulture="de"
        lex:ResxLocalizationProvider.DefaultAssembly="WPF_Localization"
        lex:ResxLocalizationProvider.DefaultDictionary="Strings"
        >
    <Grid>
        <Label Name="LabelText"

 Content="{lex:Loc }" Width="400" FontSize="54"   />
        <TextBlock Name="TextBlock" Text="{lex:Loc}" FontSize="35" Margin="22,217,378,136"/>
    </Grid>
</Window>

App link:

https://1drv.ms/u/s!As7XdG-frgtlh41bZtRBzdijPY6MOQ?e=IOBtaL