Workspace auto-switches back when firefox' "Inspect Network Request" window is displayed

STR:
1. Open firefox
2. Open Web Console (Tools -> Web Developer -> Web Console)
3. Go to e.g http://start.ubuntu.com
4. Click on any items in Web Console to bring "Inspect Network Request" window.
5. Press Ctrl+Alt+Left Arrow and don't release Ctrl+Alt until workspace is switched

Expected results:
Workspace is switched

Actual results:
Workspace is switched back to the previous one.

from #ubuntu-unity:
<htorque> great. it needed more of those "inspect network request" windows to open before i got it.

To reproduce it even more reliably, put the Inspect Network Request a bit off-screen for the current workspace.

Additionally it is not clear why the "Inspect Network Request" window is not focused but this can be a firefox bug

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.8.0+bzr2275ubuntu0+677 [origin: LP-PPA-unity-team]
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
ApportVersion: 2.0.1-0ubuntu2
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CrashDB: unity
Date: Thu Apr 12 13:24:48 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120225)
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)