The Delphi global var DecimalSeparator should contain the operating system value for floating point separator.2) If you set grid.ExcelStyleDecimalSeparator, the OS defined decimal separator will be entered when you press the dot (Del) key on the numeric keypad. It will enter either '.' or ',' depending on your OS settings.
3) If you set the editor to any of the types edFloat, edPositiveFloat, ... it will only allow the user to enter via the keyboard the operating system defined decimal separator.