WPF allows you to create localized applications with relatively little effort. The localized strings are put into resource files (.resx), one per target language, and maintained as needed. The editing facilities of Visual Studio, however, are not designed to help the localization efforts, however. The GUI can only show one resource file at a time. It would have been much more convenient if files could be edited side by side, allowing easy synchronisation and addition of missing strings. A simple open-source program Simple Resx Editor does just that.