Index: openacs-4/packages/acs-templating/tcl/form-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/tcl/form-procs.tcl,v
diff -u -N -r1.58 -r1.59
--- openacs-4/packages/acs-templating/tcl/form-procs.tcl	3 Nov 2018 19:52:29 -0000	1.58
+++ openacs-4/packages/acs-templating/tcl/form-procs.tcl	28 Dec 2018 11:24:10 -0000	1.59
@@ -633,6 +633,15 @@
         append output "<legend>$fieldset_legend</legend>"
     }
 
+    # Export variables specified by the export property as hidden
+    # formfields. (used e.g. by ad_form when specifying the -export
+    # flag)
+    if { [info exists form_properties(export)] } {
+        append output {<!-- Exported form vars START -->}
+        append output [uplevel #$level [subst {export_vars -form {$form_properties(export)}}]]
+        append output {<!-- Exported form vars END -->}
+    }
+
     # Export form ID and current form mode
     append output [export_vars -form { { form\:id $id } { form\:mode $properties(mode) } }]