[Kaitain]

I agree. This is not a useful workflow. It is typical to use a previous diagram as the template for a new/altered version. "Save As" is used to generate that new diagram and name it in one move. If you choose "duplicate" you either have to then execute a second action immediately in order to specify the new name and location, or leave it "on the stack" in your brain as something gnawing at you, and which you might forget.

This is not an intuitive or helpful way of working. I wish I hadn't updated. This is a bit of a functionality ambush for something so core and established.