Index: openacs-4/packages/acs-subsite/www/permissions/perm-include.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-subsite/www/permissions/perm-include.tcl,v
diff -u -N -r1.14.2.3 -r1.14.2.4
--- openacs-4/packages/acs-subsite/www/permissions/perm-include.tcl	4 Jul 2017 23:26:49 -0000	1.14.2.3
+++ openacs-4/packages/acs-subsite/www/permissions/perm-include.tcl	28 Jul 2017 11:54:35 -0000	1.14.2.4
@@ -7,15 +7,15 @@
     @param user_add_url URL for adding users
 } {
     {object_id:integer}
-    {return_url:localurl}
+    {return_url:localurl,optional}
     {privs { read create write delete admin }}
     {user_add_url:localurl ""}
 }
 
 set user_id [ad_conn user_id]
 set admin_p [permission::permission_p -object_id $object_id -privilege admin]
 
-if { $return_url eq "" } {
+if { (![info exists return_url] || $return_url eq "") } {
     set return_url [ad_return_url]
 }