Todo item:

Improving UI visualization of using Material nodes:
- Property editor: the context top line now shows the linkage path
  (in material and texture view mode)
- Activating new material node refreshes preview in property editor
  when in texture mode.

This should make editing textures with node materials a bit more clear.

source/blender/editors/space_buttons/buttons_context.c

@@ -236,6 +236,12 @@ static int buttons_context_path_material(ButsContextPath *path)
 			ma= give_current_material(ob, ob->actcol);
 			RNA_id_pointer_create(&ma->id, &path->ptr[path->len]);
 			path->len++;
+			
+			ma= give_node_material(ma);
+			if(ma) {
+				RNA_id_pointer_create(&ma->id, &path->ptr[path->len]);
+				path->len++;
+			}			
 			return 1;
 		}
 	}

source/blender/editors/space_buttons/space_buttons.c

@@ -356,8 +356,12 @@ static void buttons_area_listener(ScrArea *sa, wmNotifier *wmn)
 			}
 			break;
 		case NC_NODE:
-			if(wmn->action==NA_SELECTED)
+			if(wmn->action==NA_SELECTED) {
 				ED_area_tag_redraw(sa);
+				/* new active node, update texture preview */
+				if(sbuts->mainb == BCONTEXT_TEXTURE)
+					sbuts->preview= 1;
+			}
 			break;
 		/* Listener for preview render, when doing an global undo. */
 		case NC_WINDOW: