Re-add listener removed in last commit

git-svn-id: https://svn.apache.org/repos/asf/logging/chainsaw/trunk@1032185 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/log4j/chainsaw/LogPanel.java

@@ -366,6 +366,16 @@ public void windowClosing(WindowEvent e) {
     undockedFrame.setSize(new Dimension(1024, 768));
     undockedFrame.pack();
 
+    preferenceModel.addPropertyChangeListener(
+      "scrollToBottom",
+      new PropertyChangeListener() {
+        public void propertyChange(PropertyChangeEvent evt) {
+          boolean value = ((Boolean) evt.getNewValue()).booleanValue();
+          if (value) {
+            scrollToBottom();
+          }
+        }
+      });
     /*
      * Menus on which the preferencemodels rely
      */