StringResource.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary Source="StringResource.CustomMenu.xaml"/>
        <ResourceDictionary Source="StringResource.PgLoading.xaml"/>
        <ResourceDictionary Source="StringResource.PgMe.xaml"/>
    </ResourceDictionary.MergedDictionaries>
    

</ResourceDictionary>