tweaking default GDM theme for multi-head

[Dave Thomas <dave sasdatalink com>]

The system I am using Fedora on uses two monitors in 'big desktop' mode.
The default Fedora GDM theme has the logon right in the middle of the
screen, so it spans both monitors on this box. I know nothing about GDM
themes....can someone tell me how to tweak the theme so the logon box
displays off to one side?

Thanks,
Dave Thomas