Change Color of Expand control on a subform

[Renee]

I need help on how to change the color of an expand
control for a subform when there is data in the record.

If data is in the record, then I want to show the + expand
control as a different color.

Right now, hitting the + expand control will either
display the data that is in the current record, or allow
you to add data linked to the main form.

Thanks, Renee