How to use the smooth tool in weight paint mode?

Question

I'm curious as to what I need to do to use the smooth tool in weight paint mode in Blender. The notice says:

Vertex select needs to be enabled in weight paint mode.

Great! How does one enable vertex select in weight paint mode?

Answer 1

The vertex select can be enabled in the 3D View header -

With vertex select masking enabled you can use Shift-Click to select/de-select each vertex from the mask. You can also go into edit mode, select the desired vertices then go into weight paint mode.