Thank you very much for your speed!
But for a better understanding would it not be better to re-add the "locked" button next to the move button?

Yes the button is missing :
http://i.imgur.com/wbhjgx9.png

When we're admin, it would be cool to have ability to edit a post even if the topic is closed. It's a little bit annoying to have to unlock, edit and lock again.