Let me add "me too" to the list of people noticing this bug. I was going to file a report on it, but a search turned up this list.
It appears that hitting "cancel" at any point of the login, even before entering a username, will make it impossible to log into the system. "Cancel" does not return you to the Username prompt, and you cannot get focus back to where you enter passwords. Related to this may be the case where you mis-type the username. Again, there is no way to return to a place where you can enter the username again. -- You received this bug notification because you are a member of LightDM Gtk+ Greeter Development Team, which is the registrant for LightDM GTK+ Greeter. https://bugs.launchpad.net/bugs/974610 Title: can't cancel authentication Status in LightDM GTK+ Greeter: New Bug description: Hi, this is lightdm 1.2.0 without accountservice and with user list disabled. When typing a wrong username, there's no way to cancel the authentication: the cancel button doesn't work and it seems that there's no limit on the number of entered passwords. To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/974610/+subscriptions -- Mailing list: https://launchpad.net/~lightdm-gtk-greeter-team Post to : [email protected] Unsubscribe : https://launchpad.net/~lightdm-gtk-greeter-team More help : https://help.launchpad.net/ListHelp

