Crash from stylesheet due to dangling widget pointers in cache

#include <QtGui>
#include <qdebug.h>

class Widget : public QWidget
{
public:
    Widget(QWidget *parent = 0);
    ~Widget();
};

const char* pszStyleSheet = "* { color: red; }";

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    QVBoxLayout* pLayout = new QVBoxLayout(this);
    QCheckBox* pCheckBox = new QCheckBox(this);
    pLayout->addWidget(pCheckBox);
    setLayout(pLayout);

    QString szStyleSheet = QLatin1String(pszStyleSheet);
    qApp->setStyleSheet(szStyleSheet);
    qApp->setStyle(QStyleFactory::create(QLatin1String("Windows")));
}

Widget::~Widget()
{

}


int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget *w = new Widget();
    delete w;
    w = new Widget();
    w->show();

    return a.exec();
}