Index: openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml,v
diff -u -r1.60.2.5 -r1.60.2.6
--- openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml	22 Nov 2019 16:30:46 -0000	1.60.2.5
+++ openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml	29 Nov 2019 14:28:48 -0000	1.60.2.6
@@ -550,7 +550,7 @@
 			# extend the form to support categories
 			set package_id [ad_conn package_id]
 			    
-    			category::ad_form::add_widgets -form_name note -container_object_id $package_id -categorized_object_id [value_if_exists item_id]
+    			category::ad_form::add_widgets -form_name note -container_object_id $package_id -categorized_object_id [expr {[info exists item_id] ? $item_id : ""}]
 
     			ad_form -extend -name note -on_submit {
         			set category_ids [category::ad_form::get_categories -container_object_id $package_id]