I use drum maps for keyswitches for Kontakt instruments. Mostly orchestral. However, I agree with SG, would be great to be able to see it better. The contrast between text and background color is nearly non-existant. And a shot to the eyes if your using the darker interface.
I've been through the theme editor top to bottom, changing every color I could find to florescent pink, trying to find that background or the text color. And I did the same in the preferences>colors. No luck.
The only workaround I've found is zooming in really close on the drum map. And that gets quite fiddly. Change zoom on drum map and piano roll disappears...get piano roll back and drum map disappears....eventually you get them both back up and big enough to see drum map. I set it as a lens to save time.