Index: openacs-4/packages/categories/www/cadmin/category-parent-change-2.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-parent-change-2.tcl,v
diff -u -N -r1.6 -r1.7
--- openacs-4/packages/categories/www/cadmin/category-parent-change-2.tcl	29 Jun 2018 17:27:18 -0000	1.6
+++ openacs-4/packages/categories/www/cadmin/category-parent-change-2.tcl	12 Feb 2019 17:12:19 -0000	1.7
@@ -7,7 +7,7 @@
 } {
     tree_id:naturalnum,notnull
     category_id:naturalnum,notnull
-    {parent_id:naturalnum,optional [db_null]}
+    {parent_id:naturalnum,optional ""}
     {locale ""}
     object_id:naturalnum,optional
     ctx_id:naturalnum,optional