Files not saved before printng

[JH Austin]

I'm not sure you would call this is bug or just a user error, 
but I have lost a couple files recently.
Using Frescobaldi and Lilypond, after composing and printing a file correctly,
the saved file is still back-level to the printed copy.

Having a "good" printout and thinking I was finished, I exited the program, 
apparently without saving, and all my revisions disappeared.

Stupid me!  Guess I've gotten so used to modern programs that do auto-save that 
I've developed sloppy habits.

But it would be helpful to warn the user before printing if the file has not 
been saved.

I'm running:
Frescobaldi 3.1.2
Lilypond 2.20.0-1
Mac OS 10.13.4 High Sierra