Sorry, I do not see what update-manager itself can do. It sets the focus_on_map property to false so it requests from the WM to not get focus. A possible workaround for xubuntu/mythubuntu could be to set the /apps/update-notifier/auto_launch default to False in the xubuntu- system-settings package (or something like this).
** Changed in: update-manager (Ubuntu) Status: New => Incomplete -- Auto-opening Update Manager opens frontmost with xfwm4 https://bugs.launchpad.net/bugs/335928 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs