App.xaml

<?xml version="1.0" encoding="utf-8"?>
<Application xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <!-- to make the designer happy and to view default localazition strings in the designer-->
                <ResourceDictionary Source="Localization/LocSource.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>