Screen light is on as long as the charger is connected My Samsung Android GT-S5660 running 2.3.4 has its screen light on permanently as long as the charger is connected, and I don't know how to make it go off.

I admit fooling around with buttons, settings etc and somehow caused the problem in the first place. I must have gone into some 'setting' somewhere but can't recall where. Which control should I go back to so as to fix the problem?
This is an option in the developer section of settings on all android devices I believe. It is called 'Stay Awake' and the description is "Screen will never time out while charging"

If you untick this, the screen should go to sleep as normal again.