scrollbar not working in Q3ScrollView...

[sh123]

I am using QT 4.4.3 .In Q3ScrollView scrollbars will automatically come if contents size is greater than the viewable area.But this didn't happen.so I used sv->setVScrollBarMode(Q3ScrollView::AlwaysOn); as follows:

Q3ScrollView* sv = new Q3ScrollView(this);
    sv->setGeometry(0,0,110,600);
    sv->setVScrollBarMode(Q3ScrollView::AlwaysOn);
    QWidget *widget = new QWidget(sv->viewport());
    QVBoxLayout *layout = new QVBoxLayout(widget);
 
    QLabel* child1 = new QLabel("CHILD", widget);                                                                                                                                                            
 
child1->setPixmap(QPixmap(":/trolltech/examples/graphicsview/portedcanvas/img1.png"));
    child1->setGeometry(2,2,90,620);

Q3ScrollView* sv = new Q3ScrollView(this);
    sv->setGeometry(0,0,110,600);
    sv->setVScrollBarMode(Q3ScrollView::AlwaysOn);
    QWidget *widget = new QWidget(sv->viewport());
    QVBoxLayout *layout = new QVBoxLayout(widget);

    QLabel* child1 = new QLabel("CHILD", widget);                                                                                                                                                            

child1->setPixmap(QPixmap(":/trolltech/examples/graphicsview/portedcanvas/img1.png"));
    child1->setGeometry(2,2,90,620);

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After doing this the scrollbar appeared but scrolling was not happening.The scrollbar appeared as shown in the image below: