6417702: Graph in Memory tab is not redrawn immediately if changed via 'Chart' combo box

Reviewed-by: alanb, jbachorik, sjiang

src/share/classes/sun/tools/jconsole/MemoryTab.java

 /*
- * Copyright (c) 2004, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -228,6 +228,7 @@ class MemoryTab extends Tab implements ActionListener, ItemListener {
         if (ev.getStateChange() == ItemEvent.SELECTED) {
             Plotter plotter = (Plotter)plotterChoice.getSelectedItem();
             plotterPanel.setPlotter(plotter);
+            plotterPanel.repaint();
         }
     }