How to refresh a window?

[Netaro]

So, I'm doing Hillegass book, and i'm stuck on chapter 13 challenge.

The I've done it 90%, but then, one thing still remains: "Don't forget to update the window to reflect the new defaults"

 

So, how do i do that? How do i refresh a NSWindowController window? Because when i click the "reset settings" button, the state of the objects on the window (in this case, a ColorWell and a checkbox) stay the same until i manually reopen the window.