You're right. It is as you describe on my 2015 MacBook Air running 10.12.6. But on my 2009 iMac running 10.11.6, using LibreOffice, option-hyphen did produce a

You're right. It is as you describe on my 2015 MacBook Air running 10.12.6. But on my 2009 iMac running 10.11.6, using LibreOffice, option-hyphen did produce an en-dash, but command-hyphen did. So either LibreOffice or some configuration setting somewhere on this Mac is responsible for this nonstandard behavior. Thanks.