Localization files should be in a folder “localizations”. The installer does not create it.
When you change the language, the message “Your changes will take effect when System Ninja is restarted.”
The option “Make the UI background darker” reset after restarting the application.
Still not fixed. When I switch language from English into Russian, everything is normal. When I restart app, a half of Russian translation is replaced with English.
Windows 10 Insider Preview, x64