Change color on click (kgPanels)

[Be3f.]

Hi guys, here's the deal.

What I'm currently looking for is a way for a panel to change color when clicked, and switch back to the "normal" color when clicked again.
With my knowledge in lua nearly being non existing, I have no clue on how to do this, expect I guess it's in the "onclick" section.
I've tried searching the forum among others without any luck. Help will be much appreciated.