UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.78 Safari/537.36

Steps to reproduce the problem:
1. Create a snippet.
2. Write some code in it.
3. Accidentally (:)) close the Developer Tools feature.

What is the expected behavior?
"Do you want to discard your snippet?"

What went wrong?
I have to write my long and sophisticated snippet again because of my mistake. Help me. :)

Did this work before? N/A 

Chrome version: 60.0.3112.78  Channel: n/a
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: 

Using the Developer Tools on the Developer Tools, I added onbeforeunload and it worked, so perhaps it can be leveraged as a start (and switch the focus to the Sources panel and the last unsaved snippet).