Index: openacs-4/packages/xowiki/tcl/xowiki-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/xowiki-procs.tcl,v
diff -u -r1.542.2.97 -r1.542.2.98
--- openacs-4/packages/xowiki/tcl/xowiki-procs.tcl	18 Dec 2020 14:30:12 -0000	1.542.2.97
+++ openacs-4/packages/xowiki/tcl/xowiki-procs.tcl	8 Jan 2021 11:45:30 -0000	1.542.2.98
@@ -4979,9 +4979,17 @@
       :setCSSDefaults
 
       lassign [:field_names_from_form -form $form] form_vars field_names
-      array unset :__field_in_form
-      if {$form_vars} {foreach v $field_names {set :__field_in_form($v) 1}}
+      set :__field_in_form ""
+      if {$form_vars} {
+        foreach v $field_names {
+          dict set :__field_in_form $v 1
+        }
+      }
       set form_fields [:create_form_fields $field_names]
+      foreach n $field_names f $form_fields {
+        dict set :__form_fields $n $f
+      }
+      
       :load_values_into_form_fields $form_fields
 
       # deactivate form-fields and do some final sanity checks
@@ -5114,8 +5122,7 @@
     # Don't marshall/save/cache the following vars:
     #
     # array unset :__ia
-    array unset :__field_in_form
-    array unset :__field_needed
+    unset -nocomplain :__form_fields :__field_in_form  :__field_needed
   }
 
   Page instproc map_categories {category_ids} {