Some fixes;

- Armature deform options "Envelope" and "Vertexgroup" didn't combine. One
  Vertexgroup added disabled all Envelopes
- "Clear" option in WPaint Panel now sends refresh to deform
- Same for Undo in Wpaint

source/blender/src/buttons_editing.c

@@ -2932,6 +2932,7 @@ void do_fpaintbuts(unsigned short event)
 			for(a=0; a<me->totvert; a++)
 				remove_vert_defgroup (ob, defGroup, a);
 			allqueue(REDRAWVIEW3D, 0);
+			DAG_object_flush_update(G.scene, ob, OB_RECALC_DATA);
 		}
 	}
 }