Helm posframes in emacs 26

config.el

 ;; Posframe!
  ;; https://www.reddit.com/r/emacs/comments/80bdck/using_a_posframe_to_show_ivys_candidate_menu/dvcsarc
  (defvar helm-posframe-buffer nil)

  (defun helm-posframe-display (buffer &optional _resume)
    (posframe-show
      (setq helm-posframe-buffer buffer)
      :poshandler #'posframe-poshandler-frame-bottom-left-corner
      :left-fringe 10
      :width (frame-width)
      :height 16 ;; ivy/+childframe uses 16
      :respect-header-line t))

  (defun helm-posframe-cleanup ()
    (posframe-hide helm-posframe-buffer))

  (add-hook! 'helm-cleanup-hook #'helm-posframe-cleanup)
  (setq helm-display-function #'helm-posframe-display)