How to select different bones while in weight paint mode? I seem to remember being able to select different bones of a rig while in weight paint mode.

However, now when I try to do this I end up selecting a face (used for masking) instead of the bone:



How did I change this and how can I select bones while in weight paint mode?



Upon further investigation this face selection is used for masking, and bones can be selected with &#9096; Ctrl RMB.

However, I can't figure out where this behavior came from.. I've tested it in blender 2.69 through 2.73, and in every version blender defaults to selecting bones with plain  RMB and there seems to be no way to select or enable selection of faces while in weight paint mode. I couldn't find any settings regarding masking while in weight paint either.

So the real question is: What did I enable to allow this face selection masking feature?
Although the officially-suggested workflow is to select face mask by switching to Edit mode (since more powerful selection tools there), you can also quickly select faces or verts for masking In Weight Paint mode by toggling the two  buttons located on the headerbar, or simply press M or V to toggle them on/off.