When settting the longtitude and latitude values for the night color location, the decimal separator is always C locale's ".". E.g. I'm using a German locale here, and would like to set the location to Nuremberg's Hauptmarkt. Then I'd enter latitude "49,45398" and longitude "11,07736". With a comma as the decimal separator, consistent with my locale. This is not accepted by the dialog however, I have would have to enter "49.45398" and "11.07736".