Use the same ordering as item views and release before unparenting.
Change-Id: I0346342cfcaf9385d8385769795dd5ba35fc43aa
Task-number: QTBUG-46828
Reviewed-by: Liang Qi <liang.qi@theqtcompany.com>
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>