[Solved] How to selectively remove copper from a filled zone?

I am using Kicad v4.0.4

As I understand a filled zone is a polygon that is filled with copper and is connected to a net. My goal is to create another polygon within this zone, which is not filled with the copper and isn’t connected to any net. I searched about this for a bit, and came to know that such a thing is called a cutout. The documentation for Pcbnew says to right click on the zone boundary and choose the create cutout option.

As you can see, there is no create cutout option available, or maybe I’m doing something wrong. I apologize if my post seems a bit inarticulate, because my Kicad and PCB related vocabulary is quite limited at this point of time. Any help is greatly appreciated.

Place a keepout zone: