Ahshia,
The grey print margins cannot currently be changed in the options.
However, a workaround is to simply draw a box on top of the margins, and change the box's border colors. You can also make the box unselectable through it's options if you don't want it to interfere. Lastly, put this as it's condition:
=&printermode = 0
This will make it appear only in Design during form design time. When you actually print or preview, it will not appear.
Hope that helps!
Regards,
Raphaël Lalonde Lefebvre
(PS: I will delete your other thread, since there is no need for having two threads on the same topic)