Open 'color mgr' (the color globe)
click the <back color at R top
Choose your desired bground color from list on L
Click "set color" at top L
Then "OK" top R.
Silver is a good bground color for me.
(the design is mine)
If I remember right
Find the color wheel -- top left.
The screen splits but shows the colors.
Select the color you want.
Great, I didn't know that