The Qt documentation states that prepareGeometryChange() needs to be called if an item is being resized. Does that also apply when adding child items that change the size of the parent, or does the framework do that automatically when a child is added? I ask because I called prepareGeometryChange() on the parent before adding a child and the scene didn't draw correctly, whereas commenting out the function call resulted in correct scene rendering. Any advice on how to correctly use prepareGeometryChange() would be appreciated.