Program: 51856
Project: 51856
Buggy source:
@Override public Panel getButtonPanel(){
  boolean ignoreIndividualButtonAlign=false;
  String buttonalign=getButtonalign();
  if (!StringUtils.isEmpty(buttonalign)) {
    ignoreIndividualButtonAlign=true;
  }
  HorizontalPanel buttonPanel=new HorizontalPanel();
  HorizontalPanel leftButtonPanel=new HorizontalPanel();
  HorizontalPanel centerButtonPanel=new HorizontalPanel();
  HorizontalPanel rightButtonPanel=new HorizontalPanel();
  rightButtonPanel.setStylePrimaryName("String_Node_Str");
  centerButtonPanel.setStylePrimaryName("String_Node_Str");
  leftButtonPanel.setStylePrimaryName("String_Node_Str");
  for (  XulButton btn : dialogButtons) {
    this.removeChild(btn);
    Widget widget=(Widget)btn.getManagedObject();
    if (!ignoreIndividualButtonAlign) {
      String align=btn.getAlign();
      if (!StringUtils.isEmpty(align)) {
        if ("String_Node_Str".equals(align)) {
          centerButtonPanel.add(widget);
        }
 else         if ("String_Node_Str".equals(align)) {
          leftButtonPanel.add(widget);
        }
 else {
          rightButtonPanel.add(widget);
        }
      }
 else {
        rightButtonPanel.add(widget);
      }
    }
 else {
      if ("String_Node_Str".equals(buttonalign)) {
        centerButtonPanel.add(widget);
      }
 else       if ("String_Node_Str".equals(buttonalign)) {
        leftButtonPanel.add(widget);
      }
 else {
        rightButtonPanel.add(widget);
      }
    }
  }
  buttonPanel.add(leftButtonPanel);
  buttonPanel.setCellHorizontalAlignment(leftButtonPanel,HorizontalPanel.ALIGN_LEFT);
  buttonPanel.add(centerButtonPanel);
  buttonPanel.setCellHorizontalAlignment(centerButtonPanel,HorizontalPanel.ALIGN_CENTER);
  buttonPanel.setCellWidth(centerButtonPanel,"String_Node_Str");
  buttonPanel.add(rightButtonPanel);
  buttonPanel.setCellHorizontalAlignment(rightButtonPanel,HorizontalPanel.ALIGN_RIGHT);
  return buttonPanel;
}

Fixed version (ground truth):
@Override public Panel getButtonPanel(){
  boolean ignoreIndividualButtonAlign=false;
  String buttonalign=getButtonalign();
  if (!StringUtils.isEmpty(buttonalign)) {
    ignoreIndividualButtonAlign=true;
  }
  HorizontalPanel buttonPanel=new HorizontalPanel();
  HorizontalPanel leftButtonPanel=new HorizontalPanel();
  HorizontalPanel centerButtonPanel=new HorizontalPanel();
  HorizontalPanel rightButtonPanel=new HorizontalPanel();
  rightButtonPanel.setStylePrimaryName("String_Node_Str");
  centerButtonPanel.setStylePrimaryName("String_Node_Str");
  leftButtonPanel.setStylePrimaryName("String_Node_Str");
  for (  XulButton btn : dialogButtons) {
    this.removeChild(btn);
    Widget widget=(Widget)btn.getManagedObject();
    if (!ignoreIndividualButtonAlign) {
      String align=btn.getAlign();
      if (!StringUtils.isEmpty(align)) {
        if ("String_Node_Str".equals(align)) {
          centerButtonPanel.add(widget);
        }
 else         if ("String_Node_Str".equals(align)) {
          leftButtonPanel.add(widget);
        }
 else {
          rightButtonPanel.add(widget);
        }
      }
 else {
        rightButtonPanel.add(widget);
      }
    }
 else {
      if ("String_Node_Str".equals(buttonalign)) {
        centerButtonPanel.add(widget);
      }
 else       if ("String_Node_Str".equals(buttonalign)) {
        leftButtonPanel.add(widget);
      }
 else {
        rightButtonPanel.add(widget);
      }
    }
  }
  buttonPanel.add(leftButtonPanel);
  buttonPanel.setCellHorizontalAlignment(leftButtonPanel,HorizontalPanel.ALIGN_LEFT);
  buttonPanel.add(centerButtonPanel);
  buttonPanel.setCellHorizontalAlignment(centerButtonPanel,HorizontalPanel.ALIGN_CENTER);
  buttonPanel.setCellWidth(centerButtonPanel,"String_Node_Str");
  buttonPanel.add(rightButtonPanel);
  buttonPanel.setCellHorizontalAlignment(rightButtonPanel,HorizontalPanel.ALIGN_RIGHT);
  buttonPanel.setWidth("String_Node_Str");
  return buttonPanel;
}