Description of problem: In F15 gnome-control-center is pulled in through various dependencies on non-GNOME desktops (gnome-packagekit, gnome-bluetooth, ...) and gnome-sound-applet should not be started there as most of them already have a mixer applet. Please add "OnlyShowIn=GNOME;" to /etc/xdg/autostart/gnome-sound-applet.desktop. Version-Release number of selected component (if applicable): control-center-1:2.91.92-3.fc15
control-center-3.0.0.1-3.fc15 has been submitted as an update for Fedora 15. https://admin.fedoraproject.org/updates/control-center-3.0.0.1-3.fc15
Package control-center-3.0.0.1-3.fc15: * should fix your issue, * was pushed to the Fedora 15 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing control-center-3.0.0.1-3.fc15' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/control-center-3.0.0.1-3.fc15 then log in and leave karma (feedback).
control-center-3.0.0.1-3.fc15 has been pushed to the Fedora 15 stable repository. If problems still persist, please make note of it in this bug report.