TYPO3 Core

If you want to exit a content element without saving in TYPO3 7.6, the "Yes, I'm sure" button is highlighted.

In my experience, confirmation dialogues tend to highlight the "safer" action, so if you want to exit a content element without saving, the highlighted button normally will be "No, I will continue editing".

I'm posting this after I've tripped over it for about the 30est time.
I'm only used to OS X dialogues, and I haven't checked what Nielsen says about it either :-)