Comment 9 for bug 395314

I'm adding my comment here rather than to the Gnome bug tracker because I don't have an account there, and here I can reference Ubuntu versions

According to lspci my graphics card is
VGA compatible controller: nVidia Corporation G71 [GeForce 7300 GS] (rev a1)

On Jaunty the login prompt always appeared on the primary monitor (left). On Karmic (upgraded on-line today 25/Dec/09) the login prompt seems to be dependent on the mouse position as described above. I seem to recall that the mouse always was in the middle of the two screens, just to the right.

Interestingly at the point at which you have to put your mouse on the main screen to get the login prompt to appear there, you can't actually see the mouse pointer on that screen; it seems to be hidden by the Ubuntu splash screen.