--- tooltip.el	2020-08-21 15:12:24.108484748 +0200
+++ lisp/tooltip.el	2020-10-05 02:47:13.662826815 +0200
@@ -26,6 +26,7 @@
 ;;; Code:
 
 (require 'syntax)
+(require 'widget) ; for "sticky" tooltips
 
 (defvar comint-prompt-regexp)
 
@@ -164,6 +165,14 @@
   :group 'tooltip
   :version "27.1")
 
+(defcustom tooltip-enable-sticky nil
+  "Set this variable to true to enable `sticky' tooltip interface.
+This variable does not have effect when Gtk tooltips are enabled
+  (requires Emacs to be compiled with Gtk suppoart and
+  x-gtk-use-system-tootlip to be set to true)."
+  :type 'boolean
+  :group 'tooltip)
+
 
 ;;; Variables that are not customizable.
 
@@ -258,12 +267,61 @@
 	    (setf (alist-get 'border-color params) fg))
 	  (when (stringp bg)
 	    (setf (alist-get 'background-color params) bg))
-	  (x-show-tip (propertize text 'face 'tooltip)
-		      (selected-frame)
-		      params
-		      tooltip-hide-delay
-		      tooltip-x-offset
-		      tooltip-y-offset))
+          (if x-gtk-use-system-tooltips
+	      (x-show-tip (propertize text 'face 'tooltip)
+		          (selected-frame)
+		          params
+		          tooltip-hide-delay
+		          tooltip-x-offset
+		          tooltip-y-offset)
+
+            ;; we are not using gtk
+            (with-current-buffer (get-buffer-create " *tip*")
+              (let ((inhibit-read-only t))
+                (erase-buffer)
+                (remove-overlays)
+                (insert (propertize text 'face 'tooltip))
+
+                (when tooltip-enable-sticky
+                  (goto-char (point-min))
+                  (let ((cur-line 0)
+                        (lng-line 0))
+                    (while (not (eobp))
+                      (setq cur-line (- (line-end-position) (line-beginning-position)))
+                      (when (> cur-line lng-line)
+                        (setq lng-line cur-line))
+                      (forward-line))
+
+                    (newline)
+
+                    ;; (insert (propertize
+                    ;;               (make-string (- lng-line 6) ?─)
+                    ;;               'face 'tooltip))
+                    ;; (widget-insert (propertize " Sticky " 'face
+                    ;;                            'tooltip))
+                    (insert (make-string (- lng-line 6) ?─))
+                    (widget-insert " Sticky ")
+                    (widget-create 'checkbox
+                                   :notify (lambda (s &rest ignore)
+                                             (if (widget-value s)
+                                                 (progn ;; OBS nothing here yet
+                                                   ;; (when tooltip-timer
+                                                   ;;   (cancel-timer tooltip-timer)
+                                                   ;;   (setq tooltip-timer nil))
+                                                   )
+                                               ;; else
+                                               (tooltip-hide))))
+                  (use-local-map widget-keymap)
+                  (widget-setup)))
+
+                ;; this (propertize text ... ) here is unnecessary
+                ;; ... but this is just a fast hack
+                (x-show-tip (propertize text 'face 'tooltip)
+                            (selected-frame)
+		            params
+		            tooltip-hide-delay
+		            tooltip-x-offset
+		            tooltip-y-offset)))))
       (error
        (message "Error while displaying tooltip: %s" error)
        (sit-for 1)