Program: 75658
Project: 75658
Buggy source:
/** 
 * initEditorLayout - initialize the UI components of the editor
 */
private Composite initEditorLayout(Composite parent){
  Composite mainPane=new Composite(parent,SWT.NONE);
  GridLayout layout=new GridLayout();
  layout.verticalSpacing=0;
  mainPane.setLayout(layout);
  final Composite barPane=new Composite(mainPane,SWT.NONE);
  layout=new GridLayout(4,false);
  barPane.setLayout(layout);
  GridData gdata=new GridData(GridData.FILL_HORIZONTAL);
  barPane.setLayoutData(gdata);
  cmbExpList=new Combo(barPane,SWT.READ_ONLY);
  GridData layoutData=new GridData(GridData.FILL_HORIZONTAL);
  cmbExpList.setLayoutData(layoutData);
  butReset=new Button(barPane,SWT.PUSH);
  butReset.setText(Messages.getString("String_Node_Str"));
  layoutData=new GridData();
  layoutData.horizontalIndent=6;
  butReset.setLayoutData(layoutData);
  butReset.addSelectionListener(new SelectionListener(){
    public void widgetSelected(    SelectionEvent e){
      setEditorText("String_Node_Str");
      markDirty();
    }
    public void widgetDefaultSelected(    SelectionEvent e){
      widgetSelected(e);
    }
  }
);
  Label column=new Label(barPane,SWT.SEPARATOR | SWT.VERTICAL);
  layoutData=new GridData();
  layoutData.heightHint=20;
  layoutData.horizontalIndent=10;
  column.setLayoutData(layoutData);
  ano=new Label(barPane,0);
  layoutData=new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_CENTER);
  ano.setLayoutData(layoutData);
  final Composite sep=new Composite(mainPane,0);
  layoutData=new GridData(GridData.FILL_HORIZONTAL);
  layoutData.heightHint=1;
  sep.setLayoutData(layoutData);
  sep.addPaintListener(new PaintListener(){
    public void paintControl(    PaintEvent e){
      GC gc=e.gc;
      Rectangle rect=sep.getBounds();
      gc.setForeground(ColorConstants.darkGray);
      gc.drawLine(0,0,rect.width,0);
    }
  }
);
  Composite jsEditorContainer=new Composite(mainPane,SWT.NONE);
  gdata=new GridData(GridData.FILL_HORIZONTAL | GridData.FILL_VERTICAL);
  jsEditorContainer.setLayoutData(gdata);
  jsEditorContainer.setLayout(new FillLayout());
  return jsEditorContainer;
}

Fixed version (ground truth):
/** 
 * initEditorLayout - initialize the UI components of the editor
 */
private Composite initEditorLayout(Composite parent){
  Composite mainPane=new Composite(parent,SWT.NONE);
  GridLayout layout=new GridLayout();
  layout.verticalSpacing=0;
  mainPane.setLayout(layout);
  final Composite barPane=new Composite(mainPane,SWT.NONE);
  layout=new GridLayout(5,false);
  barPane.setLayout(layout);
  GridData gdata=new GridData(GridData.FILL_HORIZONTAL);
  barPane.setLayoutData(gdata);
  cmbExpList=new Combo(barPane,SWT.READ_ONLY);
  GridData layoutData=new GridData(GridData.FILL_HORIZONTAL);
  cmbExpList.setLayoutData(layoutData);
  extendedItemExpList=new Combo(barPane,SWT.READ_ONLY);
  extendedItemExpList.setLayoutData(layoutData);
  butReset=new Button(barPane,SWT.PUSH);
  butReset.setText(Messages.getString("String_Node_Str"));
  layoutData=new GridData();
  layoutData.horizontalIndent=6;
  butReset.setLayoutData(layoutData);
  butReset.addSelectionListener(new SelectionListener(){
    public void widgetSelected(    SelectionEvent e){
      setEditorText("String_Node_Str");
      markDirty();
    }
    public void widgetDefaultSelected(    SelectionEvent e){
      widgetSelected(e);
    }
  }
);
  Label column=new Label(barPane,SWT.SEPARATOR | SWT.VERTICAL);
  layoutData=new GridData();
  layoutData.heightHint=20;
  layoutData.horizontalIndent=10;
  column.setLayoutData(layoutData);
  ano=new Label(barPane,0);
  layoutData=new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_CENTER);
  ano.setLayoutData(layoutData);
  final Composite sep=new Composite(mainPane,0);
  layoutData=new GridData(GridData.FILL_HORIZONTAL);
  layoutData.heightHint=1;
  sep.setLayoutData(layoutData);
  sep.addPaintListener(new PaintListener(){
    public void paintControl(    PaintEvent e){
      GC gc=e.gc;
      Rectangle rect=sep.getBounds();
      gc.setForeground(ColorConstants.darkGray);
      gc.drawLine(0,0,rect.width,0);
    }
  }
);
  Composite jsEditorContainer=new Composite(mainPane,SWT.NONE);
  gdata=new GridData(GridData.FILL_HORIZONTAL | GridData.FILL_VERTICAL);
  jsEditorContainer.setLayoutData(gdata);
  jsEditorContainer.setLayout(new FillLayout());
  return jsEditorContainer;
}