[helm] Hide mode line and minibuffer content

helm-config-0x01.el

(setq helm-echo-input-in-header-line t)
;; Hide minibuffer when the above option is on.
(add-hook 'helm-minibuffer-set-up-hook
          #'helm-hide-minibuffer-maybe)

;; Don't use helm's own displaying mode line function
(fset 'helm-display-mode-line #'ignore)

(add-hook 'helm-after-initialize-hook
          (defun hide-mode-line-in-helm-buffer ()
            "Hide mode line in `helm-buffer'."
            (with-helm-buffer
              (setq-local mode-line-format nil))))