Program: 139138
Project: 139138
Buggy source:
/** 
 * DOC yyi create Up Down and Delete Buttons
 * @param parent
 */
private void createUpDownButtons(Composite parent){
  if (null != buttonsComp) {
    buttonsComp.dispose();
  }
  buttonsComp=masterPage.getEditor().getToolkit().createComposite(parent,SWT.NONE);
  buttonsComp.setLayout(new GridLayout(3,true));
  buttonsComp.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
  GridData buttonGridData=new GridData();
  buttonGridData.heightHint=25;
  buttonGridData.horizontalAlignment=GridData.CENTER;
  buttonGridData.verticalAlignment=GridData.FILL;
  buttonGridData.grabExcessHorizontalSpace=true;
  buttonGridData.grabExcessVerticalSpace=true;
  Button delButton=new Button(buttonsComp,SWT.NULL);
  delButton.setImage(ImageLib.getImage(ImageLib.DELETE_ACTION));
  delButton.setLayoutData(buttonGridData);
  Button moveUpButton=new Button(buttonsComp,SWT.NULL);
  moveUpButton.setText(DefaultMessagesImpl.getString("String_Node_Str"));
  moveUpButton.setLayoutData(buttonGridData);
  Button moveDownButton=new Button(buttonsComp,SWT.NULL);
  moveDownButton.setText(DefaultMessagesImpl.getString("String_Node_Str"));
  moveDownButton.setLayoutData(buttonGridData);
  delButton.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      removeSelectedElements(tree);
    }
  }
);
  moveUpButton.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      moveSelectedElements(tree,-1);
    }
  }
);
  moveDownButton.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      moveSelectedElements(tree,1);
    }
  }
);
  parent.layout();
}

Fixed version (ground truth):
/** 
 * DOC yyi create Up Down and Delete Buttons
 * @param parent
 */
private void createUpDownButtons(Composite parent){
  if (null != buttonsComp) {
    buttonsComp.dispose();
  }
  buttonsComp=masterPage.getEditor().getToolkit().createComposite(parent,SWT.NONE);
  buttonsComp.setLayout(new GridLayout(3,true));
  buttonsComp.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
  GridData buttonGridData=new GridData(SWT.CENTER,SWT.CENTER,true,false);
  Button delButton=new Button(buttonsComp,SWT.NONE);
  delButton.setImage(ImageLib.getImage(ImageLib.DELETE_ACTION));
  delButton.setLayoutData(buttonGridData);
  Button moveUpButton=new Button(buttonsComp,SWT.NONE);
  moveUpButton.setText(DefaultMessagesImpl.getString("String_Node_Str"));
  moveUpButton.setLayoutData(buttonGridData);
  Button moveDownButton=new Button(buttonsComp,SWT.NONE);
  moveDownButton.setText(DefaultMessagesImpl.getString("String_Node_Str"));
  moveDownButton.setLayoutData(buttonGridData);
  delButton.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      removeSelectedElements(tree);
    }
  }
);
  moveUpButton.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      moveSelectedElements(tree,-1);
    }
  }
);
  moveDownButton.addSelectionListener(new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      moveSelectedElements(tree,1);
    }
  }
);
  parent.layout();
}