Workspace switcher moves 1 space down when an icon is dragged close to trash

Release: Ubuntu 12.10 Quantal

While executing the test steps in Canonical/WK1_16072012 -> Ubuntu -> Unity-Manual -> Launcher -> Test Case ID Can-28 :: Version : 1 - UNITY_ Drag Icons to Trash, the following was observed.

When an icon from the launcher was dragged away from the launcher and when it is moved close to Rubbish Bin, the Workspace Switcher icon on the launcher moves 1 space down creating a blank space in between the Workspace Switcher icon on launcher and the icon above it.

While releasing the mouse button in order to drop the icon to the rubbish bin, please note that at the same time the icon of the application being dropped appears in the blank space created above workspace switcher for a very small interval of 1 second or lesser before the space gets closed.

This blank space gets closed after the icon being dragged is dropped to the rubbish bin. The workspace switcher occupies the blank space by moving 1 space up.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: unity 6.0.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-4.4-generic 3.5.0-rc6
Uname: Linux 3.5.0-4-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.3-0ubuntu4
Architecture: i386
Date: Wed Jul 18 18:17:24 2012
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)