move to workspace loses track of window entirely

[James Hunt]

Moving a window to another workspace using the context menu options "Move to Workspace right" or "Move to Another Workspace" causes unity to lose track of the window entirely - it disappears never to return.

Note: the processes associated with the windows *are* still running as shown by xlsclients.

Moving the windows manually to another workspace (by shifting the window almost off the screen to the right or bottom, then changing to the appropriate workspace and pulling the half-obscured window into that workspace) works.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.1.2+14.04.20140318-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-18.38-generic 3.13.6
Uname: Linux 3.13.0-18-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.13.3-0ubuntu1
Architecture: i386
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]
CurrentDesktop: Unity
Date: Fri Mar 21 11:36:12 2014
InstallationDate: Installed on 2010-10-21 (1247 days ago)
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
SourcePackage: unity
UpgradeStatus: Upgraded to trusty on 2013-11-01 (139 days ago)