code: public void uninstallUI(JComponent c) {
          super.uninstallUI(c);
          uninstallClientDecorations(root);
  
          layoutManager      = null;
          mouseInputListener = null;
          root               = null;
      }
docs: Invokes supers implementation to uninstall any of its state. This will
  also reset the <code>LayoutManager</code> of the <code>JRootPane</code>.
  If a <code>Component</code> has been added to the <code>JRootPane</code>
  to render the window decoration style, this method will remove it.
  Similarly, this will revert the Border and LayoutManager of the <code>
  JRootPane</code> to what it was before <code>installUI</code> was
  invoked.
  
  @param c the JRootPane to uninstall state from