QWidget::scroll doesn't update themed background for children when scrolled on Symbian

Running the attached code in resulting rendering the child widget's background is taken from 0,0,50,50 rect of theme background although it should be taken from 50,50,100,100.

QWidget scrollable;
scrollable.resize(100,100);
QLabel child(QString("@"),&scrollable);
child.resize(50,50);
scrollable.show();
scrollable.scroll(50,50);

Problem is that if we fix this we will cause huge performance impact on fast software scroller or make us not use it at all.