1.) First drag any folder from Left Tree Panel to Right Tree Panel then drop. Now Right tree Panel will show up that dragged or moved folder.
2.) Now, in Right Tree Panel expand this moved folder and drag any leaf to Left tree Panel's any folder. But don't drop it. After few seconds you will find your dragged folder will get dropped automatically.
You are not reproducing this bug with correct steps.
In your video, i can see, you are using IE9 ( Browser Mode) and Quicks (Document Mode) in developers tool. But, for reproducing this you need to change this to IE8 (Browser Mode) and IE8 standards (Document Mode).