Photoshop :: Not To Paint In Transparent...

I can't remember how that feature was called, but I remember, in earlier versions, that there was a check box in the Brush toolbar to avoid paint on transparent areas when painting over Alpha images. I was able, in example, to paint over a stroke with the brush and don't worry about painting outside, you know... Now there is a feature in the "Mode" selector of the Brush toolbar to paint "behind" or to take effect only over the transparent areas, but... I want just the opposite! Well, I suppose this is just a mind slipping and it must be right under my nose,