Cannot implement dragging in QML Treeview

The MouseArea used inside the QML TreeView (as __mouseArea hidden property) has the preventStealing property set to !Settings.hasTouchScreen. On a desktop computer with no touchscreen, this makes it impossible to wrap the TreeView in a MouseArea which would implement dragging.

I think that either !Settings.hasTouchScreen is not the correct way to initialized this property, or that TreeView should expose a property to override its behaviour.