how can I prevent that Studio 2017 automatically replaces a lower case letter by an uppercase letter after a dot (e.g. after an abbreviation followed by a dot)?

How can I prevent that Studio 2017 automatically replaces a lower case letter by an uppercase letter after a dot (e.g. after an abbreviation followed by a dot)?

I use Studio 2017 since 2 weeks now, didn't click any settings that might have caused the issue. In Studio 2014 this never occurred.