ListView focus with VisualItemModel

When use a VisualItemModel in a ListView, the items which are flicked out of the visible area are not destroyed but all their child item'focus are set to false. The real problem is that they are not restored when they are re-flick in the visible area.
I've dig in a bit and found that items's parent are set to null/removed from the graphicsScene when use in VisualItemModel, which cause all the focus chain to be set to false.
the top Item focus handling is correct though.