I don't know why this bug was only fixed in unity and not in update- manager, but here's a workaround for those of us not using unity (since all the other workarounds posted here don't work):
sudo apt-get install wmctrl wmctrl -F -r "Software Updater" -e 0,0,10,600,700 -- You received this bug notification because you are a member of compiz packagers, which is subscribed to compiz in Ubuntu. https://bugs.launchpad.net/bugs/1301776 Title: Update manager is really small and not resizeable To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1301776/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : compiz@lists.launchpad.net Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp