wrong position of window reported after switching workspaces

After switching workspaces by using the mouse to click on applications, the pointer position reported is not correct which cause dropdown menus to be displayed at the wrong coordinates.

Because workspace switching using the keyboard or the workspace switcher on the launcher works, I'll provide detailed instructions on how to reproduce this behavior. I also attached a sample tcl/tk program that shows this issue very well. You can execute this by installing `tcl8.5` and `tk8.5` and running `tclsh8.5 unity_bug.tcl`.

Detailed instructions to reproduce behavior:
1. Open an application (eg firefox,chrome,thunderbird) in the top-left workspace.
2. Run the sample program I provided in the bottom right workspace.
3. Now click the file menu in the sample program, to see the position of this window relative to the top left corner of the workspace.
4. Now switch to the apllication in the top-left workspace by clicking that application in the launcher (do NOT use the workspace switcher icon or the keyboard)
5. switch back to the sample program by clicking the sample program in the launcher (again do NOT use the workspace switcher icon or the keyboard)
6. click the menu again, note that the position reported is the position of step 3 plus your screen resolution. Note that because of this the actual menu will show in the wrong place (bottom left corner of the workspace).

After you drag the window, the behavior is correct again.

NOTE that this is not a bug in tcl/tk!
Open http://www.w3schools.com/tags/tryit.asp?filename=tryhtml_select in Chrome.
Then switch workspaces by clicking a program in another workspace and switch back to chrome, the dropdown menu will not show up.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: unity 7.1.2+13.10.20131014.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
Date: Fri Nov 22 13:43:06 2013
InstallationDate: Installed on 2013-11-21 (1 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MarkForUpload: True
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)