How do you rename an animator controller?

I have an animator controller named “image 16”. I want to rename it to “Coin Animator” on Unity 2018.2 Personal. I’ve tried renaming it using key F2 but for some reason it doesn’t work. Does anyone have any suggestions or solutions?

A bit late, and therefore a different version (2021), but I’ve found that if you rename the FILE, you get a warning in the inspector, which also offers to rename the controller. It does indeed rename the CONTROLLER, not the file, as I thought before I tried it.
Maybe it’s a recent improvement, I don’t know.

(Reason for necro, this thread popped up when I searched for this specific issue.)