Inside a JFrame's container, I have a JPanel. I have a JScrollPane inside that which currently has a JTextArea object. Using a menu item, I want to be able to change the contents of the scroll pane to a JTree. I can currently do it by getting the JPanel and then adding a new JScollPane object containing the JTree. However, when I do so, the frame shrinks and then (nearly) instantly resizes. I want the frame to 'stay put'.