Index: openacs-4/packages/acs-core-docs/www/tutorial-categories.html
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-core-docs/www/tutorial-categories.html,v
diff -u -r1.13.4.4 -r1.13.4.5
--- openacs-4/packages/acs-core-docs/www/tutorial-categories.html	17 Oct 2013 09:08:35 -0000	1.13.4.4
+++ openacs-4/packages/acs-core-docs/www/tutorial-categories.html	24 Oct 2014 14:34:02 -0000	1.13.4.5
@@ -196,7 +196,7 @@
  	  <code class="computeroutput">-from_clause</code>.</p><pre class="programlisting">
  	  	set use_categories_p [parameter::get -parameter "EnableCategoriesP" -default 0]
 
-		if { $use_categories_p == 1 &amp;&amp; [exists_and_not_null category_id] } {
+		if { $use_categories_p == 1 &amp;&amp; $category_id ne "" } {
 
 			set from_clause "category_object_map com, acs_named_objects nam"
 			set_where_clause "com.object_id = qa.entry_id and