Dynamic Lighting/Fog question

okay, so i am playing around with my first map with dynamic lighting and fog of war. i mostly have it the way i want it (it's not as gloomy as i want it, i would it rather look like dim lighting, but i think i will probably figure that out) but i can't seem to figure out how to reset it from my testing it so that the fog of war is back in place. is there a reset map to unexplored command i am missing somewhere?

I sometimes also needed to search for this, because I do not use it that often... There is a button in the toolbar concerning manual modifications to the fog of war ("eye", 4th from bottom) and the bottom option there is to "Reset Explorable Darkness".