I have downloaded and installed both version 3.12.4 and 3.12.5 and I am still having the same problem with the regional settings. I change the Decimal Grouping Symbol to a space and leave the Decimal Separator Symbol as a "." and this works until I close DC and then when I reopen DC it has reverted to the default of Decimal Grouping Symbol of "." and Decimal Separator Symbol of "." If I use a "," (comma) as the Decimal Grouping Symbol then I have no problem with the symbols. It is only if I use the space " " that I have the problem.