Robert, thank you. That looks a much better design, because it provides a well-framed choice. I'd tack an "Anyway" onto the "Shut Down" button, as a hint to those who didn't read the text that something risky is about to happen.
People here have made statements of form "It's no use asking for authentication, because someone could just hold down the power button ... unless it's physically inaccessible." I don't think that logic follows. It's true that someone could just hold down the power button -- but a large percentage of people *won't* do that, because they'll realize something unexpected is going on. I suggest that security is not necessarily the only purpose of an authentication dialog, and it may not be the purpose here. Another purpose is to reduce dataloss by getting more people to pause and think about what they're about to do. And I think that more people will do that with an authentication dialog than with a vanilla confirmation dialog. The tradeoff is that an authentication dialog doesn't (with the current API, at least) allow for including a "Log Out Instead" button. So, here is a wireframe of the single-session case, followed by wireframes of three options for the multi-session case: A: a refinement of Robert's alternative, with "Log Out Instead", "Cancel", and "Shut Down Anyway" B: an any-user authentication dialog, with "Cancel" and "Continue" C: an administrator-only authentication dialog, with "Cancel" and "Continue". ** Attachment added: "The single-session dialog, and three options for the multi-session dialog" https://bugs.launchpad.net/ubuntu/+source/unity-greeter/+bug/861171/+attachment/3454312/+files/shut-down-multiple-sessions.png -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-session in Ubuntu. https://bugs.launchpad.net/bugs/861171 Title: Shutdown from greeter does nothing when multiple accounts open Status in The Session Menu: Triaged Status in LightDM GTK+ Greeter: Triaged Status in OEM Priority Project: In Progress Status in OEM Priority Project precise series: In Progress Status in Unity Greeter: Triaged Status in “gnome-session” package in Ubuntu: Confirmed Status in “indicator-session” package in Ubuntu: Triaged Status in “policykit” package in Ubuntu: Confirmed Status in “unity-greeter” package in Ubuntu: Triaged Bug description: Selecting shutdown from the greeter does nothing when multiple accounts are open. This is because the lightdm user (which the greeter runs as) does not have permission to shutdown while sessions are open. Inside a normal session this would just return you to the login screen. The solution is either for the indicator to say "not allowed" or to run a PolicyKit frontend in the greeter than can get the required permissions to perform the shutdown. To manage notifications about this bug go to: https://bugs.launchpad.net/indicator-session/+bug/861171/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp