I used to have that problem when using xterm: white text on black background. I worked around it by writing a script that gave each new xterm instance a differe

I used to have that problem when using xterm: white text on black background. I worked around it by writing a script that gave each new xterm instance a different dark background colour. Each window by its own felt like it was still black but when you put two next to each other you'd notice the difference in hue. Then I switched to mate-terminal which put a nice big scrollbar in the right-side border of each window, so I didn't need that script any more.