diff --git a/source/clog-gui.lisp b/source/clog-gui.lisp
index dce33c0..ce9103b 100644
--- a/source/clog-gui.lisp
+++ b/source/clog-gui.lisp
@@ -842,7 +842,8 @@ the browser."))
 (defmethod window-close ((obj clog-gui-window))
   (let ((app (connection-data-item obj "clog-gui")))
     (remhash (format nil "~A" (html-id obj)) (windows app))
-    (destroy (window-select-item obj))
+    (when (window-select app)
+      (destroy (window-select-item obj)))
     (remove-from-dom obj)
     (fire-on-window-change nil app)
     (fire-on-window-close obj)))
@@ -1356,7 +1357,7 @@ Calls on-input with t if confirmed or nil if canceled."
     (unless left
       (setf (left win) (unit :px (- (/ (inner-width (window body)) 2.0)
 				    (/ (width win) 2.0)))))
-    (setf (visible win) t)
+    (setf (visiblep win) t)
     (when modal
       (window-make-modal win))
     (set-on-click cancel (lambda (obj)
diff --git a/tutorial/23-tutorial.lisp b/tutorial/23-tutorial.lisp
index 04e8742..0092b35 100644
--- a/tutorial/23-tutorial.lisp
+++ b/tutorial/23-tutorial.lisp
@@ -5,16 +5,20 @@
 (in-package :clog-user)
 
 ;; This is a simple demo using semaphores to wait for user input
+;; ask demonstrates the mechanics in general and the modal dialog
+;; example show a more practical example.
 (defun ask (obj)
   (let ((result nil)
 	(hold (bordeaux-threads:make-semaphore))
 	(q-box (create-div obj)))
     (set-on-click (create-button q-box :content "Yes")
 		  (lambda (obj)
+		    (declare (ignore obj))
 		    (setf result :yes)
 		    (bordeaux-threads:signal-semaphore hold)))
     (set-on-click (create-button q-box :content "No")
 		  (lambda (obj)
+		    (declare (ignore obj))
 		    (setf result :no)
 		    (bordeaux-threads:signal-semaphore hold)))
     (bordeaux-threads:wait-on-semaphore hold :timeout 10)
@@ -22,10 +26,26 @@
     result))
 
 (defun on-new-window (body)
+  ;; clog-gui can be mixed in to non-desktop environments, but
+  ;; to use you must call first clog-gui-initialize
+  (clog-gui-initialize body)
   (set-on-click (create-button body :content
 			       "Click for my question. You have 10 seconds to answer.")
 		(lambda (obj)
-		  (create-div body :content (ask body))))
+		  (declare (ignore obj))		  
+		  ;; ask returns once an answer is given or times out
+		  (create-div body :content (ask body))
+		  ;; once ask returns with its answer (yes no or nil for timeout)
+		  ;; the next statment is processed to open a dialog
+		  (let ((hold (bordeaux-threads:make-semaphore)))
+		    (confirm-dialog body "Are you sure?"
+				    (lambda (answer)
+				      (if answer
+					  (create-div body :content "Great!")
+					  (create-div body :content "Next time be sure!"))
+				      (bordeaux-threads:signal-semaphore hold)))
+		    (bordeaux-threads:wait-on-semaphore hold :timeout 60)
+		    (create-div body :content "Thank you for answering!"))))
   (run body))
 
 (defun start-tutorial ()