No where does 'acpi-support' perform a shutdown... The only way would be a failed Hibernate, however that wouldn't draw pretty shutdown messages (Nils: do you see messages or 'usplash' pop up after you press escape?).
The dialogue is drawn by 'gnome-session' which then uses either 'gnome- power-manager' or 'gdm' to do its deeds, but they are only acting as middleware. The keystroke is causing a UI issue. Is it something like 'escape' is causing the window to be destroyed, which is in-turn causing some assertion to fail. Or more likely, 'escape' is being interpreted as 'ANY_KEY' and using the currently right-most button ("Shutdown") to be activated? -- System shuts down when pressing esc, when the logout dialog is shown https://launchpad.net/bugs/46319 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs