--- a/jdk/src/share/classes/javax/swing/JTree.java	Mon Aug 24 18:21:47 2009 +0400
+++ b/jdk/src/share/classes/javax/swing/JTree.java	Mon Aug 24 19:22:38 2009 +0400
@@ -3498,8 +3498,9 @@
      * @see Scrollable#getScrollableTracksViewportWidth
      */
     public boolean getScrollableTracksViewportWidth() {
-        if (getParent() instanceof JViewport) {
-            return getParent().getWidth() > getPreferredSize().width;
+        JViewport port = SwingUtilities2.getViewport(this);
+        if (port != null) {
+            return port.getWidth() > getPreferredSize().width;
         }
         return false;
     }
@@ -3514,8 +3515,9 @@
      * @see Scrollable#getScrollableTracksViewportHeight
      */
     public boolean getScrollableTracksViewportHeight() {
-        if (getParent() instanceof JViewport) {
-            return getParent().getHeight() > getPreferredSize().height;
+        JViewport port = SwingUtilities2.getViewport(this);
+        if (port != null) {
+            return port.getHeight() > getPreferredSize().height;
         }
         return false;
     }