Forwarded from: https://launchpad.net/distros/ubuntu/+source/gdm/+bug/35835

Start the Login Window Preferences app, choose "local" and then "plain" in the Style menu (first entry starting from the top). As you can see, in the "Menu Bar" section you can choose whether to display the "actions menu" or not in the login window. Make your choice. No problem so far. Now back to the "Style" menu entry and switch to "Themed": the "Menu Bar" section is not provided in the "Themed" section of the dialog, though the previous choice you made in the "Plain" section regarding actions menu etc. will apply to the themed greeter as well. That is, to enable/disable the "Show actions menu" in the themed greeter you have to switch to the "Plain" greeter first: I think it's very confusing