It's because Show Desktop, when invoked for the second time, "unmininize"
all the windows. Because you already have some restored, it will look like
it did nothing. Not that I like this behaviour, though...

2012/4/13 palimmo <email address hidden>

> It seems solved now.
> But.. does show desktop (through alt+Tab) work at the first "movement"? I
> have to repeat it twice to get the desktop....
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/877778
>
> Title:
>  Showdesktoped window contents invisible in window spread
>
> Status in Unity:
>  Fix Released
> Status in Unity Distro Priority:
>  Fix Committed
> Status in “unity” package in Ubuntu:
>  Fix Committed
>
> Bug description:
>  1. have two firefox windows opened
>  2. alt-tab until getting to "show desktop"
>  3. click on the firefox icon in the launcher to restore the last focused
> firefox window
>  4. click again on the firefox icon in the launcher
>    -> the  minimized window is scaled, but invisible (empty placeholder)
>
>  I'm using the Oneiric proposed channel, so it might have something to
>  do with the latest updates to Unity or Compiz.
>
>  ProblemType: Bug
>  DistroRelease: Ubuntu 11.10
>  Package: unity 4.24.0-0ubuntu1
>  ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
>  Uname: Linux 3.0.0-12-generic i686
>  NonfreeKernelModules: nvidia
>  .proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory:
> '/proc/driver/nvidia/gpus/0'
>  .proc.driver.nvidia.registry: Binary: ""
>  .proc.driver.nvidia.version:
>   NVRM version: NVIDIA UNIX x86 Kernel Module  280.13  Wed Jul 27 16:55:43
> PDT 2011
>   GCC version:  gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)
>  .tmp.unity.support.test.0:
>
>  ApportVersion: 1.23-0ubuntu3
>  Architecture: i386
>  CompizPlugins:
> [core,bailer,detection,composite,opengl,decor,mousepoll,vpswitch,regex,animation,snap,expo,move,compiztoolbox,place,grid,imgpng,gnomecompat,wall,ezoom,workarounds,resize,fade,unitymtgrabhandles,scale,session,unityshell]
>  CompositorRunning: compiz
>  Date: Tue Oct 18 19:11:09 2011
>  DistUpgraded: Log time: 2011-09-13 11:04:09.297261
>  DistroCodename: oneiric
>  DistroVariant: ubuntu
>  DkmsStatus:
>   nvidia-current, 280.13, 3.0.0-12-generic, i686: installed
>   nvidia-current-updates, 280.13, 3.0.0-12-generic, i686: installed
>  GraphicsCard:
>   nVidia Corporation GT216 [GeForce GT 220] [10de:0a20] (rev a2) (prog-if
> 00 [VGA controller])
>     Subsystem: BFG Tech Device [19f1:113c]
>  InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta i386 (20110909)
>  JockeyStatus:
>   xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary,
> Disabled, Not in use)
>   xorg:nvidia_current_updates - NVIDIA accelerated graphics driver
> (post-release updates) (Proprietary, Enabled, In use)
>  MachineType: Acer Aspire M1201
>  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-12-generic
> root=UUID=ab49ff83-e28a-460e-84bc-6bcddae18d1e ro quiet splash vt.handoff=7
>  SourcePackage: unity
>  UpgradeStatus: Upgraded to oneiric on 2011-09-22 (26 days ago)
>  XorgConf:
>   Section "Device"
>    Identifier  "Default Device"
>    Option      "NoLogo"        "True"
>   EndSection
>  dmi.bios.date: 08/21/2008
>  dmi.bios.vendor: American Megatrends Inc.
>  dmi.bios.version: R03-B1
>  dmi.board.asset.tag: To Be Filled By O.E.M.
>  dmi.board.name: RS740DVF
>  dmi.board.vendor: Acer
>  dmi.chassis.type: 3
>  dmi.chassis.vendor: Acer
>  dmi.chassis.version: 1.0
>  dmi.modalias:
> dmi:bvnAmericanMegatrendsInc.:bvrR03-B1:bd08/21/2008:svnAcer:pnAspireM1201:pvr:rvnAcer:rnRS740DVF:rvr:cvnAcer:ct3:cvr1.0:
>  dmi.product.name: Aspire M1201
>  dmi.sys.vendor: Acer
>  version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu5
>  version.libdrm2: libdrm2 2.4.26-1ubuntu1
>  version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu3
>  version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
>  version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu3
>  version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
>  version.xserver-xorg: xserver-xorg 1:7.6+7ubuntu7
>  version.xserver-xorg-input-evdev: xserver-xorg-input-evdev
> 1:2.6.0-1ubuntu13
>  version.xserver-xorg-video-ati: xserver-xorg-video-ati
> 1:6.14.99~git20110811.g93fc084-0ubuntu1
>  version.xserver-xorg-video-intel: xserver-xorg-video-intel
> 2:2.15.901-1ubuntu2
>  version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau
> 1:0.0.16+git20110411+8378443-1
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/unity/+bug/877778/+subscriptions
>



-- 
Pablo Almeida
http://www.google.com/profiles/pabloalmeidaff9