Variable: mode-line-in-non-selected-windows
mode-line-in-non-selected-windows is a customizable variable defined
in window.c.
Value
t
Documentation
Non-nil means to use mode-line-inactive face in non-selected windows.
If the minibuffer is active, the minibuffer-scroll-window mode line
is displayed in the mode-line face.
This variable was added, or its default value changed, in Emacs 22.1.
Probably introduced at or before Emacs version 22.1.
Source Code
// Defined in /usr/src/emacs/src/window.c
DEFVAR_BOOL ("mode-line-in-non-selected-windows", mode_line_in_non_selected_windows,
doc: /* Non-nil means to use `mode-line-inactive' face in non-selected windows.
If the minibuffer is active, the `minibuffer-scroll-window' mode line
is displayed in the `mode-line' face. */);