On Mac OS X 10.5.8, Drawer widget in a MainWindow disappears after returning from full screen mode.

// QT4 Includes
#include <QApplication>
#include <QWidget>
#include <QMainWindow>
#include <QPushButton>
#include <QHBoxLayout>

int main(int argc, char **argv)
{
    // Handle command line parameters for GUI
    QApplication app(argc, argv);

    QMainWindow * myWindow = new QMainWindow();
    QWidget * center = new QWidget();
    myWindow -> setCentralWidget(center);

    QHBoxLayout * h = new QHBoxLayout();
    center -> setLayout(h);

    QWidget * drawer = new QWidget(myWindow, Qt::Drawer);
    drawer -> hide();

    QPushButton * show = new QPushButton("Show Drawer");
    app.connect (show, SIGNAL(clicked()),
        drawer, SLOT(show()));
    h -> addWidget(show);

    QPushButton * hide = new QPushButton("Hide Drawer");
    app.connect (hide, SIGNAL(clicked()),
        drawer, SLOT(hide()));
    h -> addWidget(hide);

    myWindow -> show();
    myWindow -> raise();

    if (0)
    {
        myWindow -> setWindowState(Qt::WindowFullScreen);
        myWindow -> setWindowState(Qt::WindowNoState);
    }
    
    app.exec();
}