Update: Now the internal display is correctly disabled and the external display is set to its correct native resolution when gnome has started up (docked boot, haven't tried an undocked boot). The login screen still exhibits the original wrong behaviour, but this is far better than before.
Update: Now the internal display is correctly disabled and the external display is set to its correct native resolution when gnome has started up (docked boot, haven't tried an undocked boot). The login screen still exhibits the original wrong behaviour, but this is far better than before.