How to get the fully qualified classname to show in PhpStorm's window header?

First of, please don't tag Jeffrey, I'm sure he gets asked about his PhpStorm setup too much as is.

I recently read this article about Jeffrey's PhpStorm setup, and noticed the window header shows the fully qualified classname instead of either just the file name or the full path to the file. In my opinion this looks much cleaner, but I can't find anything on how to do this. Does anyone here know?