Since upgrading to virt-manager 0.8.0 (Fedora 12), you can no longer view the CPU, disk, and network usage of guests all at once, as the View->Graph menu option only allowed you to select one of the three. It would be nice if you could add all three columns at the same time.
This has been fixed upstream: http://hg.fedorahosted.org/hg/virt-manager/rev/7449fa221c45
virt-manager-0.8.1-1.fc12 has been submitted as an update for Fedora 12. http://admin.fedoraproject.org/updates/virt-manager-0.8.1-1.fc12
virt-manager-0.8.1-1.fc12 has been pushed to the Fedora 12 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with su -c 'yum --enablerepo=updates-testing update virt-manager'. You can provide feedback for this update here: http://admin.fedoraproject.org/updates/F12/FEDORA-2009-12603
Fixed in virt-manager-0.8.2-1.fc12, now in stable.