OK, this is a weird one, and not terribly important although it did make me go "huh?" for a couple of days. I'm curious as to whether this is a bug and what causes it. It surely can't be intentional?
I'm using mutt-1.5.14-4 as seen on Fedora 7, compiled with ncurses 5.6, in an xterm (X.Org 6.8.99.903(227)) with default colours (i.e. in normal operation the xterm displays black text on a white background). "mutt -n -F /dev/null" comes up in white on a black background. Display an email that doesn't completely fill the screen, and it's still white on black. Type ":color normal green black" and now it's green on black. All fine so far. Now type ":color error red default" and the unoccupied part of the screen below the email suddenly turns white (along with the right- hand-sides of all header lines) even though it has nothing to do with the "error" colour setting. Typing ":color error white black" (to put it back the way it was) does not fix this either. It turns out that the colour of the unoccupied area below the email is controlled by "color tilde" even though tilde is set to off (and that's the one colour I'd failed to set in my .muttrc). I'm not sure this is intuitive: I shouldn't be able to set the colour of something that isn't there, and it would be better if these lines were the same colour as the email when tilde is turned off. It also turns out that specifying "default" for any one colour switches the whole of mutt from the default white-on-black into black-on-white, except where colour settings have been specified. I find that a bit weird. imc