QMdiSubWindow resizing in 4.3

Does it possible to resize QMdiSubWindow by resizing internal window.
The code is illustrate that resizing works wrong except if you try to resize whole QMdiSubWindow.

Thanks a lot.

Code:

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mwindow::mwindow()
        : QMainWindow()
{
    workspace=new QMdiArea;
    setCentralWidget(workspace);
 
    menubar=new QMenuBar(this);
    setMenuBar(menubar);
    taction=menubar->addAction("test");
    connect(taction, SIGNAL(triggered( bool )), this, SLOT(action()));
}
 
 
mwindow::~mwindow()
{}
 
void mwindow::action()
{
 
    QWidget *tw=new QWidget(this);
    QVBoxLayout *tlayout=new QVBoxLayout(tw);
    QPushButton *button=new QPushButton(tw);
    tlayout->addWidget(button);
 
    // resizing working good here
    workspace->addSubWindow(tw)->resize(200,200);
 
    tw->show();
   // Trying to resize internal window. No effect. does it possible?
    tw->resize(100,100);
}

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