After Firefox is launched 'Minimize Maximize Close' and 'Show desktop' stop working

[Enrico B. Accenti]

Binary package hint: firefox

Whenever firefox is opened, the three buttons Minimize Maximize and Close disappear.
Show Desktop becomes faulty and if pressed an error message appear :"Your window manager does not support the show desktop button, or you are not running a window manager:

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: firefox 3.6.3+nobinonly-0ubuntu4
ProcVersionSignature: Ubuntu 2.6.34-3.10-generic 2.6.34
Uname: Linux 2.6.34-3-generic i686
Architecture: i386
Date: Fri May 28 18:33:07 2010
FirefoxPackages:
 firefox 3.6.3+nobinonly-0ubuntu4
 firefox-gnome-support 3.6.3+nobinonly-0ubuntu4
 firefox-branding 3.6.3+nobinonly-0ubuntu4
 abroswer N/A
 abrowser-branding N/A
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100427.1)
ProcEnviron:
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: firefox

[Freddy Martinez (freddymartinez9)]

I can not reproduce this behavior. How can I reproduce this bug?

[Launchpad Janitor (janitor)]

[Expired for firefox (Ubuntu) because there has been no activity for 60 days.]