Program: 68999
Project: 68999
Buggy source:
private JPanel buildSourcePanel(){
  final JPanel sourcePanel=new JPanel();
  sourcePanel.setLayout(new GridBagLayout());
  int yPosition=0;
  JPanel titlePanel=new JPanel();
  titlePanel.setLayout(new GridBagLayout());
  JPanel newSourceDialog=new JPanel();
  newSourceDialog.setLayout(new GridBagLayout());
  JPanel oldSourceDialog=new JPanel();
  oldSourceDialog.setLayout(new GridBagLayout());
  final JLabel sourcePanelTitle=addPanelTitleToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JLabel sourcePanelDescription=addPanelDescriptionToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JLabel differenceGeneratorDescription=addPanelDescriptionToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JLabel sourcePanelDescription2=addPanelDescriptionToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JButton sourceFolderBrowseButton=new JButton("String_Node_Str");
  sourceFolderBrowseButton.addActionListener(new ActionListener(){
    @Override public void actionPerformed(    java.awt.event.ActionEvent e){
      JFileChooser chooser=new JFileChooser();
      String currentDirectory=sourceFolderField.getText();
      if ((currentDirectory == null) || (currentDirectory.trim().equals("String_Node_Str"))) {
        currentDirectory=System.getProperty("String_Node_Str");
      }
      chooser.setCurrentDirectory(new java.io.File(currentDirectory));
      chooser.setDialogTitle("String_Node_Str");
      chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
      chooser.setAcceptAllFileFilterUsed(false);
      chooser.addChoosableFileFilter(new FileNameExtensionFilter("String_Node_Str","String_Node_Str"));
      chooser.addChoosableFileFilter(new FileFilter(){
        public boolean accept(        File f){
          return f.isDirectory();
        }
        public String getDescription(){
          return "String_Node_Str";
        }
      }
);
      if (chooser.showOpenDialog(sourcePanel) == JFileChooser.APPROVE_OPTION) {
        sourceFolderField.setText(chooser.getSelectedFile().getAbsolutePath());
        BurpPropertiesManager.getBurpPropertiesManager().setSourceFolder(sourceFolderField.getText());
      }
    }
  }
);
  sourceFolderField=addTextFieldToGridBagLayout("String_Node_Str",sourcePanel,yPosition++,BurpPropertiesManager.SOURCE_FOLDER_KEY,sourceFolderBrowseButton);
  final JButton oldSourceFolderBrowseButton=new JButton("String_Node_Str");
  oldSourceFolderBrowseButton.addActionListener(new ActionListener(){
    @Override public void actionPerformed(    java.awt.event.ActionEvent e){
      JFileChooser chooser2=new JFileChooser();
      String currentDirectory=sourceFolderField.getText();
      if ((currentDirectory == null) || (currentDirectory.trim().equals("String_Node_Str"))) {
        currentDirectory=System.getProperty("String_Node_Str");
      }
      chooser2.setCurrentDirectory(new java.io.File(currentDirectory));
      chooser2.setDialogTitle("String_Node_Str");
      chooser2.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
      chooser2.setAcceptAllFileFilterUsed(false);
      chooser2.addChoosableFileFilter(new FileNameExtensionFilter("String_Node_Str","String_Node_Str"));
      chooser2.addChoosableFileFilter(new FileFilter(){
        public boolean accept(        File f){
          return f.isDirectory();
        }
        public String getDescription(){
          return "String_Node_Str";
        }
      }
);
      if (chooser2.showOpenDialog(sourcePanel) == JFileChooser.APPROVE_OPTION) {
        oldSourceFolderField.setText(chooser2.getSelectedFile().getAbsolutePath());
        BurpPropertiesManager.getBurpPropertiesManager().setOldSourceFolder(oldSourceFolderField.getText());
      }
    }
  }
);
  oldSourceFolderField=addTextFieldToGridBagLayout("String_Node_Str",sourcePanel,yPosition++,BurpPropertiesManager.OLD_SOURCE_FOLDER_KEY,oldSourceFolderBrowseButton);
  return sourcePanel;
}

Fixed version (ground truth):
private JPanel buildSourcePanel(){
  final JPanel sourcePanel=new JPanel();
  sourcePanel.setLayout(new GridBagLayout());
  int yPosition=0;
  JPanel titlePanel=new JPanel();
  titlePanel.setLayout(new GridBagLayout());
  JPanel newSourceDialog=new JPanel();
  newSourceDialog.setLayout(new GridBagLayout());
  JPanel oldSourceDialog=new JPanel();
  oldSourceDialog.setLayout(new GridBagLayout());
  final JLabel sourcePanelTitle=addPanelTitleToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JLabel sourcePanelDescription=addPanelDescriptionToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JLabel differenceGeneratorDescription=addPanelDescriptionToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JLabel sourcePanelDescription2=addPanelDescriptionToGridBagLayout("String_Node_Str",sourcePanel,yPosition++);
  final JButton sourceFolderBrowseButton=new JButton("String_Node_Str");
  sourceFolderBrowseButton.addActionListener(new ActionListener(){
    @Override public void actionPerformed(    java.awt.event.ActionEvent e){
      JFileChooser chooser=new JFileChooser();
      String currentDirectory=sourceFolderField.getText();
      if ((currentDirectory == null) || (currentDirectory.trim().equals("String_Node_Str"))) {
        currentDirectory=System.getProperty("String_Node_Str");
      }
      chooser.setCurrentDirectory(new java.io.File(currentDirectory));
      chooser.setDialogTitle("String_Node_Str");
      chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
      chooser.setAcceptAllFileFilterUsed(false);
      chooser.addChoosableFileFilter(new FileNameExtensionFilter("String_Node_Str","String_Node_Str"));
      chooser.addChoosableFileFilter(new FileFilter(){
        public boolean accept(        File f){
          return f.isDirectory();
        }
        public String getDescription(){
          return "String_Node_Str";
        }
      }
);
      if (chooser.showOpenDialog(sourcePanel) == JFileChooser.APPROVE_OPTION) {
        sourceFolderField.setText(chooser.getSelectedFile().getAbsolutePath());
        BurpPropertiesManager.getBurpPropertiesManager().setSourceFolder(sourceFolderField.getText());
      }
    }
  }
);
  sourceFolderField=addTextFieldToGridBagLayout("String_Node_Str",sourcePanel,yPosition++,BurpPropertiesManager.SOURCE_FOLDER_KEY,sourceFolderBrowseButton);
  final JButton oldSourceFolderBrowseButton=new JButton("String_Node_Str");
  oldSourceFolderBrowseButton.addActionListener(new ActionListener(){
    @Override public void actionPerformed(    java.awt.event.ActionEvent e){
      JFileChooser chooser2=new JFileChooser();
      String currentDirectory=oldSourceFolderField.getText();
      if ((currentDirectory == null) || (currentDirectory.trim().equals("String_Node_Str"))) {
        currentDirectory=System.getProperty("String_Node_Str");
      }
      chooser2.setCurrentDirectory(new java.io.File(currentDirectory));
      chooser2.setDialogTitle("String_Node_Str");
      chooser2.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
      chooser2.setAcceptAllFileFilterUsed(false);
      chooser2.addChoosableFileFilter(new FileNameExtensionFilter("String_Node_Str","String_Node_Str"));
      chooser2.addChoosableFileFilter(new FileFilter(){
        public boolean accept(        File f){
          return f.isDirectory();
        }
        public String getDescription(){
          return "String_Node_Str";
        }
      }
);
      if (chooser2.showOpenDialog(sourcePanel) == JFileChooser.APPROVE_OPTION) {
        oldSourceFolderField.setText(chooser2.getSelectedFile().getAbsolutePath());
        BurpPropertiesManager.getBurpPropertiesManager().setOldSourceFolder(oldSourceFolderField.getText());
      }
    }
  }
);
  oldSourceFolderField=addTextFieldToGridBagLayout("String_Node_Str",sourcePanel,yPosition++,BurpPropertiesManager.OLD_SOURCE_FOLDER_KEY,oldSourceFolderBrowseButton);
  return sourcePanel;
}