Item cannot be re parented to Layouts in the navigator

Item cannot be re parented to Layouts in the navigator.

(1) Add import for QtQuick.Layoyt 1.1
(2)Create a Row and a RowLayout using the item library.
(3)Create another item (Rectangle, any Control)
(4) Re parent new item to Row (does work)
(5) Re parent new item to RowLayout (does not work)

This makes QtQuick.Layouts pretty much unusable in the Designer.

We get differents types for QObject back which back could be worked around by only using the simple type but that can be break in a other way.