Index: openacs-4/packages/categories/www/cadmin/tree-view.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/tree-view.tcl,v
diff -u -r1.21 -r1.22
--- openacs-4/packages/categories/www/cadmin/tree-view.tcl	26 Apr 2018 08:56:37 -0000	1.21
+++ openacs-4/packages/categories/www/cadmin/tree-view.tcl	9 May 2018 15:33:30 -0000	1.22
@@ -75,7 +75,7 @@
     }
 }
 
-set elements {}
+set elements [list]
 
 if { $can_write_p } {
     lappend elements edit {
@@ -130,8 +130,8 @@
     }
 }
 
-set actions {}
-set bulk_actions {}
+set actions [list]
+set bulk_actions [list]
 if { $can_write_p } {
     set bulk_actions {
 	"#categories.Delete#" "category-delete" "#categories.Delete_category_link_title#"