Cannot bring nested components to Row type

If I have UI with a Row element defined it looks like this:

Now, if I take any element from the components gallery and drag it to the form view (Rectangle in this case) I lose the visibility of the Row and cannot drop the new component into it and outcome is that my new object is outside of the Row positioner.

What I would expect to happen is that 2D view shows me the Row item as well and I can drop things as child to it so resulting QML would look like:

also the width and height could be changed to be related to the parent (with responsible layouts).