Sometimes I don't want to display the mode-line .

This minor mode helps me switching it on and off:

(defvar-local hidden-mode-line-mode nil) (define-minor-mode hidden-mode-line-mode "Minor mode to hide the mode-line in the current buffer." :init-value nil :global t :variable hidden-mode-line-mode :group 'editing-basics (if hidden-mode-line-mode (setq hide-mode-line mode-line-format mode-line-format nil) (setq mode-line-format hide-mode-line hide-mode-line nil)) (force-mode-line-update) ;; Apparently force-mode-line-update is not always enough to ;; redisplay the mode-line (redraw-display) (when (and (called-interactively-p 'interactive) hidden-mode-line-mode) (run-with-idle-timer 0 nil 'message (concat "Hidden Mode Line Mode enabled. " "Use M-x hidden-mode-line-mode to make the mode-line appear.")))) ;; If you want to hide the mode-line in every buffer by default ;; (add-hook 'after-change-major-mode-hook 'hidden-mode-line-mode)