Wouldn't it be nice if the user could toggle between using the comma or the period as the decimal point when entering numbers. I am a Quicken user since its DOS days and this used to be available to European users.
The comma and period separators can be specified, but they are global and static. That is, you can't change them within a Quicken session.
See the file C:\ProgramData\Quicken\config\QUICKEN.INI and look for the specifications for sDecimal and sThousand.