Index: openacs-4/packages/categories/tcl/category-trees-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/tcl/category-trees-procs.tcl,v
diff -u -N -r1.31.2.12 -r1.31.2.13
--- openacs-4/packages/categories/tcl/category-trees-procs.tcl	25 Nov 2019 09:31:10 -0000	1.31.2.12
+++ openacs-4/packages/categories/tcl/category-trees-procs.tcl	3 May 2020 17:41:51 -0000	1.31.2.13
@@ -318,7 +318,7 @@
             select tree_id, subtree_category_id, assign_single_p,
                    require_category_p, widget
             from category_tree_map
-            where object_id in ([join $object_id_list ", "])
+            where object_id in ([ns_dbquotelist $object_id_list])
         }] {
             lappend result [list $tree_id [get_name $tree_id $locale] $subtree_category_id $assign_single_p $require_category_p $widget]
         }