QGraphicsView::scale does not work properly.

I'm using QGraphicsView::scale to zoom in and zoom out my view. Sometimes, especially in zooming out, I lose some part of my items on sceen. It is more interesting that whole QGraphicsRectItem does not disappear while some parts of rect item disappear.

Unfortunately QT doc does not help much: http://qt.nokia.com/doc/4.6/qgraphicsview.html#scale

My suspicion is while zooming out line, it rounds edges of rect to zero and I lose edge, but why some edges are disappeared and others stay.

How can I solve this problem ?

Please post the implementation of your custom item class, especially its boundingRect() and paint() members. Of course provided you have custom items.