diff --git a/Kapitel 4/4.2.9/controls-treeview/src/main/java/de/javafxbuch/MainApp.java b/Kapitel 4/4.2.9/controls-treeview/src/main/java/de/javafxbuch/MainApp.java
index 22081fe..af8ae52 100644
--- a/Kapitel 4/4.2.9/controls-treeview/src/main/java/de/javafxbuch/MainApp.java	
+++ b/Kapitel 4/4.2.9/controls-treeview/src/main/java/de/javafxbuch/MainApp.java	
@@ -49,11 +49,10 @@ protected void updateItem(Color item, boolean empty) {
                 .add(new TreeItem<Color>(Color.BLUE));
         StackPane pane = new StackPane(treeView);
         Scene scene = new Scene(pane, 300, 250);
+        scene.getStylesheets().add(getClass().getResource("tree.css").toExternalForm());
 
-        primaryStage.setTitle(
-                "TableView Demo");
+		primaryStage.setTitle("TableView Demo");
         primaryStage.setScene(scene);
-
         primaryStage.show();
     }
 
diff --git a/Kapitel 4/4.2.9/controls-treeview/src/main/resources/de/javafxbuch/tree.css b/Kapitel 4/4.2.9/controls-treeview/src/main/resources/de/javafxbuch/tree.css
new file mode 100644
index 0000000..4ca88e3
--- /dev/null
+++ b/Kapitel 4/4.2.9/controls-treeview/src/main/resources/de/javafxbuch/tree.css	
@@ -0,0 +1,7 @@
+.tree-cell > .tree-disclosure-node > .arrow {
+    -fx-rotate: 0;
+}
+
+.tree-cell:expanded > .tree-disclosure-node > .arrow {
+    -fx-rotate: 90;
+}