How do you see the list of cc'd people in a sent email?

Using Mail version 10.1 and OS 10.12.1.

When I wanted to see the list of people I cc'd in an email, I used to be able to click on the part in the address line where it says, "& 5 more." Now when I click on it nothing happens.

The only way I can see the list is to click on reply all and open a new email and they'll all be listed there.

Am I missing the way to show this list in this version?