QGraphicsProxyWidget is not transparent proxy

So, I have QTreeView embedded in QGraphicsProxyWidget. And QTreeView does not auto expand branches while drag and dropping due to incorrect calculations of coordinates.

How it doesn't work.

There is void timerEvent(QTimerEvent *event) in QTreeView class:

QPoint pos = d->viewport->mapFromGlobal(QCursor::pos()); 
if (state() == QAbstractItemView::DraggingState
    && d->viewport->rect().contains(pos)) {
    QModelIndex index = indexAt(pos);
    setExpanded(index, !isExpanded(index));
}

Error is in "QPoint pos = d->viewport->mapFromGlobal(QCursor::pos());". It tries to map global coordinates to viewport's coordinates, but viewport's rect EQUALS the rect of QGraphicsProxyWidget in QGraphicsScene! And rect of QGraphicsProxyWidget in QGraphicsScene is always the same (x=70, y=0), independently of MainWindow position on the screen!

How can I solve the problem?

PS Yes, I called setAutoExpandDelay(10);
d->openTimer.stop();