I like to have a white background for ALL of my audioclips.  
To do this take Sonar X1 or X2 and set your colors.
Export this (preferences -> colors) to a color set file.
Then start the new Sonar 2015. Import this color set file in to the new Sonar 2015.  
I have my white clips back. Bouncing audio results in a white background.
Maybe this does also with differnet background colors 1... 10 (I have not tested)