If you’ve installed Midnight Commander and haven’t changed the default colors, when you try to access a dropdown menu you may see this:

REALLY hard to read that menu, isn’t it? Wouldn’t you rather see this?

To fix the unreadable menus, just make sure Midnight Commander is not open, then use any text editor (such as nano) to open ~/.mc/ini:

nano ~/.mc/ini

Assuming that there is no existing [Colors] section in the file, just add this at the bottom of the file (if the second line exceeds the blog column width, just use copy and paste to get it all):

[Colors] base_color=default,default:menu=black,cyan:menuhot=brightmagenta,cyan:menusel=white,blue:menuhotsel=brightmagenta,blue

If there is an existing [Colors] section, you can try tweaking it using the parameters shown above. If you have a very recent version of Midnight Commander (which you probably will have if you are running Ubuntu), then instead of menu= you’ll need to use menunormal=, as shown here:

[Colors] base_color=default,default:menunormal=black,cyan:menuhot=brightmagenta,cyan:menusel=white,blue:menuhotsel=brightmagenta,blue

Note that for some reason the base_color parameter must appear, or the other items are ignored. Save the change, exit the editor, and open Midnight Commander. If you then close Midnight Commander, you may find that the position of the [Colors] section has moved within the ini file — apparently Midnight Commander rewrites the file when you close it — but if you don’t like the changes you can remove the [Colors] section to reverse the change.

I figured out how to do this after reading this blog post:
Ajnasz Blog – Midnight Commander colors and themes
Another source of information is:
Zagura’s blog – Midnight Commander Color Themes