Install with package-install-from-file and enable with M-x mini-popup-mode RET.
;; Configure a height function (Example for Vertico)
(defun mini-popup-height-resize ()
(* (1+ (min vertico--total vertico-count)) (default-line-height)))
(defun mini-popup-height-fixed ()
(* (1+ (if vertico--input vertico-count 0)) (default-line-height)))
(setq mini-popup--height-function #'mini-popup-height-fixed)
;; Disable the minibuffer resizing of Vertico (HACK)
(advice-add #'vertico--resize-window :around
(lambda (&rest args)
(unless mini-popup-mode
(apply args))))
;; Ensure that the popup is updated after refresh (Consult-specific)
(add-hook 'consult--completion-refresh-hook
(lambda (&rest _) (mini-popup--setup)) 99)