Only one Sculpt mode brush isn't working With Blender 2.79 I'm trying to use the Smooth brush on the monkey head, nothing happens. Yet when I use the SculpDraw brush with Strength at 0 and use the Autosmooth it works as a smooth brush for now.

I'm wondering is there a setting I disabled by accident? 
I already have Strength for the Smooth Brush at 1 and it does nothing. I know that in the past the brush disappeared and I had to make a new Smooth brush with Brush>Sculpt Tool>Smooth it worked once, now it doesn't do anything.

How can I get the brush to work reliably again?
I opened 2 instances of Blender, in one of them I hit in the 

File>Load Factory Settings

I used the other opened Blender to copy settings and layouts and all the user preferences.

I was hoping for something less drastic but it doesn't seem to be another solution.