My default application language setting is "System default", which is in my case Dutch. When asking something in this forum or helping (trying to help) others I switch the Application language to English UK.
When I'm done I want to switch back to "System Default" but at that time the language dropdown list contains many "empty" lines and the "System Default" is one of those empty lines.
When I cancel and then go back into the language setting, the dropdown list with languages is complete again.