Selection with RMB + SPACE

Hello,

when using selection with RMB + SPACE in order to select the right 
object between overlapping objects, I can't manage to see the 
highlighted object.

I understand that when hitting SPACE, the color of the object should 
change a bit. I think a thin red line is drawn to highlight object. But 
I'm color-blind to red and I really can't see that slight highlighting.

Is there a place where I could change the color of the highlight in this 
process? or the width of the line that is added?

FWIW, I can see normal highlighting (thicker red line) well enough.

Thank you.

O.C.