Index: openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl,v
diff -u -N -r1.7 -r1.8
--- openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl	29 Jun 2018 17:27:18 -0000	1.7
+++ openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl	29 Nov 2019 14:28:48 -0000	1.8
@@ -31,8 +31,8 @@
 set page_title [_ categories.Tree_view_title]
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar [list \
 			 [export_vars -no_empty -base tree-copy { {tree_id $target_tree_id} locale object_id ctx_id }] \
 			 [_ categories.Action_copy_tree]] \