Code review comment for lp:~osomon/unity-2d/dnd-reorder-apps

Also, it seems that Florian has some code to further simplify the DND code: https://code.launchpad.net/~fboucault/unity-2d/drag_drop_qml_item
Specifically, commits 393 and 394.

It would be interesting to see if it's possible to merge these changes too, if you think that they make sense (I have not looked at them much yet, as Florian pointed them out to me just a few minutes ago)