Program: 123065
Project: 123065
Buggy source:
private void createTabFolderField(Composite parent){
  folder=new CTabFolder(parent,SWT.NONE);
  folder.setLayoutData(new GridData(GridData.FILL_BOTH));
  folder.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      updateButtons();
    }
  }
);
  userTabItem=new CTabItem(folder,SWT.NONE);
  userTabItem.setText(Messages.getString("String_Node_Str"));
  systemTabItem=new CTabItem(folder,SWT.NONE);
  systemTabItem.setText(Messages.getString("String_Node_Str"));
  folder.setSelection(userTabItem);
  folder.setSimple(false);
  ISelectionChangedListener listListener=new ISelectionChangedListener(){
    public void selectionChanged(    SelectionChangedEvent event){
      updateButtons();
    }
  }
;
  Composite userComposite=new Composite(folder,SWT.NONE);
  userComposite.setLayout(new GridLayout());
  userComposite.setLayoutData(new GridData(GridData.FILL_BOTH));
  userViewer=new ListViewer(userComposite,SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL| SWT.BORDER);
  userViewer.setLabelProvider(new RoutineRecordLabelProvider());
  userViewer.setContentProvider(ArrayContentProvider.getInstance());
  userViewer.setInput(userRoutines);
  userViewer.getList().setLayoutData(new GridData(GridData.FILL_BOTH));
  userViewer.addSelectionChangedListener(listListener);
  userTabItem.setControl(userComposite);
  Composite systemComposite=new Composite(folder,SWT.NONE);
  systemComposite.setLayout(new GridLayout());
  systemComposite.setLayoutData(new GridData(GridData.FILL_BOTH));
  systemViewer=new ListViewer(systemComposite,SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL| SWT.BORDER);
  systemViewer.setLabelProvider(new RoutineRecordLabelProvider());
  systemViewer.setContentProvider(ArrayContentProvider.getInstance());
  systemViewer.setInput(systemRoutines);
  systemViewer.getList().setLayoutData(new GridData(GridData.FILL_BOTH));
  systemViewer.addSelectionChangedListener(listListener);
  systemTabItem.setControl(systemComposite);
}

Fixed version (ground truth):
private void createTabFolderField(Composite parent){
  folder=new CTabFolder(parent,SWT.NONE);
  folder.setLayoutData(new GridData(GridData.FILL_BOTH));
  folder.addSelectionListener(new SelectionAdapter(){
    @Override public void widgetSelected(    SelectionEvent e){
      updateButtons();
    }
  }
);
  userTabItem=new CTabItem(folder,SWT.NONE);
  userTabItem.setText(Messages.getString("String_Node_Str"));
  systemTabItem=new CTabItem(folder,SWT.NONE);
  systemTabItem.setText(Messages.getString("String_Node_Str"));
  folder.setSelection(userTabItem);
  folder.setSimple(false);
  ISelectionChangedListener listListener=new ISelectionChangedListener(){
    @Override public void selectionChanged(    SelectionChangedEvent event){
      updateButtons();
    }
  }
;
  Composite userComposite=new Composite(folder,SWT.NONE);
  userComposite.setLayout(new GridLayout());
  userComposite.setLayoutData(new GridData(GridData.FILL_BOTH));
  userViewer=new ListViewer(userComposite,SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL| SWT.BORDER);
  userViewer.setLabelProvider(new RoutineRecordLabelProvider());
  userViewer.setContentProvider(ArrayContentProvider.getInstance());
  userViewer.setInput(userRoutines);
  userViewer.getList().setLayoutData(new GridData(GridData.FILL_BOTH));
  userViewer.addSelectionChangedListener(listListener);
  userTabItem.setControl(userComposite);
  Composite systemComposite=new Composite(folder,SWT.NONE);
  systemComposite.setLayout(new GridLayout());
  systemComposite.setLayoutData(new GridData(GridData.FILL_BOTH));
  systemViewer=new ListViewer(systemComposite,SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL| SWT.BORDER);
  systemViewer.setLabelProvider(new RoutineRecordLabelProvider());
  systemViewer.setContentProvider(ArrayContentProvider.getInstance());
  systemViewer.setInput(systemRoutines);
  systemViewer.getList().setLayoutData(new GridData(GridData.FILL_BOTH));
  systemViewer.addSelectionChangedListener(listListener);
  systemTabItem.setControl(systemComposite);
}