DefaultFgBg resource

If true, c3270 will use the terminal's default foreground color instead of specifying the curses color white, and it will use the terminal's default background color instead of specifying the curses color black. This is helpful in two cases: for emulators such as gnome-terminal whose usual representation of a black background is a murky gray, and for emulators configured with a black foreground and a white background, so that c3270's screen will appear the same way.

defaultFgBg will be set to true automatically if the environment variable COLORTERM is set to gnome-terminal.

Note that this resource and option are available only if c3270 has been built with a version of ncurses that supports default foreground and background colors, and if the terminal and its associated terminfo entry also support it (it is usually implemented as ANSI color 9).