Re-ordering objects in Hierarchy is not always possible first time user drags an object. Sometimes user has to drag the object more than twice before the object is placed at the right place in Hierarchy.

To reproduce:
- Open attached project and launch "AngryBots" scene
- Grab the "Player" object (with children) at the bottom of the Hierarchy window and drag it up to place it between the top two objects in Hierarchy
- Observe that nothing happens
- Try a couple of times until you succeed

Expected result: As a user I would expect to be able to drag any object (and its children) to any position in the Hierarchy and expect the object to be placed at the right position first time I drag and drop.