Program: 51902
Project: 51902
Buggy source:
public void setButtons(final BasicDialog d){
  if (buttons == null) {
    return;
  }
  for (  String buttonName : buttons) {
    DialogButton thisButton=DialogButton.valueOf(buttonName.trim().toUpperCase());
    SwtButton swtButton=null;
    SwtButton existingButton=(this.getDocument() != null) ? (SwtButton)this.getElementById(this.getId() + "String_Node_Str" + buttonName.trim().toLowerCase()) : null;
    if (this.getId() != null && existingButton != null) {
      swtButton=existingButton;
      Widget w=(Widget)existingButton.getManagedObject();
      if ((w == null) || (w.isDisposed())) {
        Button button=d.createButton(thisButton,false);
        swtButton.setButton(button);
      }
    }
 else {
      Button button=d.createButton(thisButton,false);
      swtButton=new SwtButton(button){
        @Override public void setVisible(        boolean visible){
          super.setVisible(visible);
          d.getShell().layout(true);
        }
      }
;
      swtButton.setId(this.getId() + "String_Node_Str" + buttonName.trim().toLowerCase());
      this.addChild(swtButton);
    }
switch (thisButton) {
case ACCEPT:
      if ((getButtonlabelaccept() != null) && (getButtonlabelaccept().trim().length() > 0)) {
        swtButton.setLabel(getButtonlabelaccept());
      }
    if ((getOndialogaccept() != null) && (getOndialogaccept().trim().length() > 0)) {
      swtButton.setOnclick(getOndialogaccept());
    }
  break;
case CANCEL:
if ((getButtonlabelcancel() != null) && (getButtonlabelcancel().trim().length() > 0)) {
  swtButton.setLabel(getButtonlabelcancel());
}
if ((getOndialogcancel() != null) && (getOndialogcancel().trim().length() > 0)) {
swtButton.setOnclick(getOndialogcancel());
}
break;
case EXTRA1:
if ((getButtonlabelextra1() != null) && (getButtonlabelextra1().trim().length() > 0)) {
swtButton.setLabel(getButtonlabelextra1());
}
if ((getOndialogextra1() != null) && (getOndialogextra1().trim().length() > 0)) {
swtButton.setOnclick(getOndialogextra1());
}
break;
case EXTRA2:
if ((getButtonlabelextra2() != null) && (getButtonlabelextra2().trim().length() > 0)) {
swtButton.setLabel(getButtonlabelextra2());
}
if ((getOndialogextra2() != null) && (getOndialogextra2().trim().length() > 0)) {
swtButton.setOnclick(getOndialogextra2());
}
break;
}
}
}

Fixed version (ground truth):
public void setButtons(final BasicDialog d){
  if (buttons == null) {
    return;
  }
  for (  String buttonName : buttons) {
    DialogButton thisButton=DialogButton.valueOf(buttonName.trim().toUpperCase());
    SwtButton swtButton=null;
    SwtButton existingButton=(this.getDocument() != null) ? (SwtButton)this.getElementById(this.getId() + "String_Node_Str" + buttonName.trim().toLowerCase()) : null;
    if (this.getId() != null && existingButton != null) {
      swtButton=existingButton;
      Widget w=(Widget)existingButton.getManagedObject();
      if ((w == null) || (w.isDisposed())) {
        Button button=d.createButton(thisButton,false);
        swtButton.setButton(button);
      }
    }
 else {
      Button button=d.createButton(thisButton,false);
      swtButton=new SwtButton(button);
      swtButton.setId(this.getId() + "String_Node_Str" + buttonName.trim().toLowerCase());
      this.addChild(swtButton);
    }
switch (thisButton) {
case ACCEPT:
      if ((getButtonlabelaccept() != null) && (getButtonlabelaccept().trim().length() > 0)) {
        swtButton.setLabel(getButtonlabelaccept());
      }
    if ((getOndialogaccept() != null) && (getOndialogaccept().trim().length() > 0)) {
      swtButton.setOnclick(getOndialogaccept());
    }
  break;
case CANCEL:
if ((getButtonlabelcancel() != null) && (getButtonlabelcancel().trim().length() > 0)) {
  swtButton.setLabel(getButtonlabelcancel());
}
if ((getOndialogcancel() != null) && (getOndialogcancel().trim().length() > 0)) {
swtButton.setOnclick(getOndialogcancel());
}
break;
case EXTRA1:
if ((getButtonlabelextra1() != null) && (getButtonlabelextra1().trim().length() > 0)) {
swtButton.setLabel(getButtonlabelextra1());
}
if ((getOndialogextra1() != null) && (getOndialogextra1().trim().length() > 0)) {
swtButton.setOnclick(getOndialogextra1());
}
break;
case EXTRA2:
if ((getButtonlabelextra2() != null) && (getButtonlabelextra2().trim().length() > 0)) {
swtButton.setLabel(getButtonlabelextra2());
}
if ((getOndialogextra2() != null) && (getOndialogextra2().trim().length() > 0)) {
swtButton.setOnclick(getOndialogextra2());
}
break;
}
}
}