delete dock button is inactive

I have too many docks and makes my active window too small. When I right click on the dock to bring up the docky settings and then click the delete dock button, nothing happens. The delete dock button is lit as if it is active.

The intended action: to delete the extra dock on the side. I only need one dock; I've already got one at the bottom of the screen. I want the delete dock button to delete the dock on the side.

Action that happened when I clicked the delete dock button: nothing happened.

The attached screenshot depicts 2 extra docks that I want to delete with the delete dock button.