Without a working /etc/X11/xorg.conf (e.g. remove it), system-config-display comes up at 800x600. This means the OK and Cancel buttons at the bottom of the dialog aren't visible. I had to guess Alt+O, Enter.
On every machine I have handy, the s-c-d window comes up at about 640x480. Your _display_ might be coming up at something smaller than 800x600, but that's not s-c-d's fault but X's. Can you provide the X log from starting up at this tiny resolution without a config file?
Reporter, could you please reply to the previous question? If you won't reply in one month, I will have to close this bug as INSUFFICIENT_DATA. Thank you.
Since there are insufficient details provided in this report for us to investigate the issue further, and we have not received feedback to the information we have requested above, we will assume the problem was not reproducible, or has been fixed in one of the updates we have released for the reporter's distribution. Users who have experienced this problem are encouraged to upgrade to the latest update of their distribution, and if this issue turns out to still be reproducible in the latest update, please reopen this bug with additional information. Closing as INSUFFICIENT_DATA.