Index: openacs-4/packages/theme-zen/lib/layouts/zen3.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/theme-zen/lib/layouts/zen3.tcl,v
diff -u -r1.3 -r1.4
--- openacs-4/packages/theme-zen/lib/layouts/zen3.tcl	20 Dec 2007 13:50:37 -0000	1.3
+++ openacs-4/packages/theme-zen/lib/layouts/zen3.tcl	27 Oct 2014 16:41:59 -0000	1.4
@@ -31,19 +31,19 @@
     return_url:onevalue
 }
 
-if {![exists_and_not_null action_string]} {
+if {![info exists action_string]} {
     set action_string ""
 }
 
-if {![exists_and_not_null theme_id]} {
+if {![info exists theme_id]} {
     set theme_id ""
 }
 
-if {![exists_and_not_null return_url]} {
+if {![info exists return_url]} {
     set return_url ""
 }
 
-if { [exists_and_not_null resource_dir] } {
+if { [info exists resource_dir] && $resource_dir ne "" } {
     portal::set_page_css $resource_dir
 }