For some reason the paint weight tool is now applying changes to entire poylgons rather than being a gradiated smear like in the tutorials. I no longer have the kind of control needed to do a decent job of weighting. What must I do to get it back into gradiated mode? I've tried futzing with the brush opacity, profile, and radii, but with no success.

This has happened before, but I was able to get it back by pressing the Reset Tool button. That no longer works.

Also, what is the key phrase needed to find help on things not covered in the Tool Help... for painting weights? The help says "For all other brush settings, see the Painting guide." Well, I've searched many things and looked under Painting and I haven't found anything that covers the items on the Paint Skin Weights page that aren't covered in the Tool Help...