How can I set color of sketcher in creo 2.0

I want to set black background color in sketcher,but I set gray background color in 3D

I can't split their color when I set background color from File-->option-->system color -->background color,hey change together

How can I split their color ?

3D background color is gray (like picture A)

A

2D Sketch background color is black (like picture B)

B

How can I make them show different color?

Thank you