Propagation of MousePressEvents to QGraphicsItems very inaccurate at top and left side of Items.

MousePressEvent is called for QGraphicsItems (veryfied for QGraphicsPolygonItem and QGraphicsEllipseItem) even if the user clicks to the top or to the left of the item.
This is reproducable in the Elastic Nodes example: Zoom in until one node covers a large area of the screen. The node can be activated by clicking significantly to the left or top of the node. However on the bottom right side, selection is pixel-accurate.
This problem also applies to QGraphicsPolygonItem. If Items are small and the zoom level is high, one item can entirely block another item from being selected, if they are placed next to each other.

Additional info as per request: Example program that shows the issue as attachment