Fix [#19820] linking material nodes in node editor doesn't update the material preview

source/blender/editors/space_buttons/space_buttons.c

@@ -322,6 +322,7 @@ static void buttons_area_listener(ScrArea *sa, wmNotifier *wmn)
 			switch(wmn->data) {
 				case ND_SHADING:
 				case ND_SHADING_DRAW:
+				case ND_NODES:
 					/* currently works by redraws... if preview is set, it (re)starts job */
 					sbuts->preview= 1;
 					break;