MouseArea's drag.target crashes when we pass an inline item, instead of an item id

When, instead of passing a reference to an existing element, we pass an inline element to drag.target, qmlviewer.exe crashes.

I would have expected the inline element to be dynamically created and moved around.

Use case : I have an element, say an image. I want the image to be draggable, but instead of dragging it directly, I want to drag a "ghost" of the image (the same image, but with lower opacity), as it is extensively done in windows and Mac OS. I would define this "ghost" inline in the drag target, and expect it to be instanciated when the user starts dragging the picture

import Qt 4.7

Item {
	height:200
	width:200

	MouseArea {
		anchors.fill: parent
		drag.maximumX: 200
		drag.maximumY: 200
		drag.target: Rectangle { width: 50; height: 50; color: "grey"}	//crashes qmlviewer.exe
		
		/*
		drag.target: dragTarget			//works
		Rectangle {	id: dragTarget;	width: 50; height: 50; color: "grey" }
		*/
	}
}