 
 (defun snails-update-select-line ()
   "Update select line status."
-  ;; Update current line number.
-  (setq snails-select-line-number (line-number-at-pos))
   ;; Update select line overlay postion.
   (move-overlay snails-select-line-overlay
                 (point-at-bol)

  (interactive)
  (with-current-buffer snails-content-buffer
    ;; Goto current line.
    (goto-line snails-select-line-number)
    ;; Jump to previous candidate item position.
    (snails-jump-to-previous-item)
    ;; Update select line.

(defun snails-candidate-get-info ()
  (with-current-buffer snails-content-buffer
    ;; Goto candidate content overlay position.
    (goto-char (overlay-start snails-select-line-overlay))
    (end-of-line)
    (backward-char)

