JFileChooser leaves grey box after closing - why?

Question

Hi all,
I have a tabbed pane with 2 tabs. Each tab has 3 other panels, top, middle and bottom. On the frame in which this tabbed pane is contained there is a menubar, on which there is a File menu and a number of options.
When one of these options, the "open" item is selected, a JFileChooser opens (contained in the middle panel). However, once this is closed, a grey square remains. On changing tabs, everything seems to be fine, but the problem persists with the original tab where the file was opened.
Does anyone know how I can get rid of this grey square?
Thanks,
John

Answer 1

Ok. I include the code of interest. The whole source is copyrighted and it is too difficult to make a self-contained example. This would require just about as many files as the real project does. Below are the stuff that is needed.
   // The tabbed pane.
   private JTabbedPane tabs;
   // The current tab;
   private JPanel currentTab;
   // The top, middle and bottom panels.
   private JPanel top, bottom;
   // The scroll panel for the middle.
   private JScrollPane middleComplete;
   // The table.
   private JTable table;
   // Constructor, initialises display.
   public SyslogViewer()
      // Set basic properties of the frame.
      // Allow window events to be handled.
      addWindowListener(new WindowHandler());
      // Get the content pane.
      Container contentPane= this.getContentPane();
      // Create windowing componenets.
      JMenuBar menuBar= setupMenuBar();
      // setupTabs will set currentTab.
      tabs= setupTabs();
      // There are three tabs, top, middleComplete and bottom.
      table= new JTable();
      // Add windowing components.
      setJMenuBar(menuBar);
      contentPane.add(tabs);
      // The scroll pane for the middle.
      middleComplete= new JScrollPane(table);
      // Add the content panels to the current tab.
      // Must use the middle panel with the scroller so add middleComplete.
      currentTab.add(top, BorderLayout.NORTH);
      currentTab.add(middleComplete, BorderLayout.CENTER);
      currentTab.add(bottom, BorderLayout.SOUTH);
      // Make the frame viewable.
      setVisible(true);
    }The above method is called first. At this stage, it should be noted that table will contain nothing nor will middleComplete.
Next to be called is the event handler from the menu items.
      // What to do when item is selected.
      public void actionPerformed(ActionEvent ae)
         // name has been set.
         if (name.equals("Open"))
            // Startup a JFileChooser.
            JFileChooser jfc= new JFileChooser();
            int openedOK= jfc.showOpenDialog(middleComplete);
            if (openedOK == JFileChooser.APPROVE_OPTION)
               // Open and read the file.
               File file = jfc.getSelectedFile();
               // code to read in file
               // contents are processed and stored in a local variable of
               // SyslogViewer
               // Create the table using the data.
               table= setupTable();  
               middleComplete= new JScrollPane(table);
               currentTab.add(middleComplete,BorderLayout.CENTER);
            else
               textArea.append("Error opening");
           ...When my tabs change, I remove top, middleComplete and bottom and add them to the new tab, setting currentTab each time.
It should be noted that when I used to pass the file into the constructor I did not have any problems.
Any ideas?
Thanks,
John