Deleting an object and undoing the deletion doesn't always show child objects in correct order

To repro, create a object structure shown in the picture 1. Then delete the parent object (sphere) and undo deletion. The child object order has changed as seen in picture 2.

Not a big deal, but child object order should be preserved. Also, the incorrect order seems to be simply a display issue, since changing to master slide and back will correct the order.