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 -N -r1.540 -r1.541
--- openacs-4/packages/xowiki/tcl/xowiki-procs.tcl	20 Jan 2019 20:41:14 -0000	1.540
+++ openacs-4/packages/xowiki/tcl/xowiki-procs.tcl	21 Jan 2019 19:19:31 -0000	1.541
@@ -130,15 +130,15 @@
         # the package parameter "use_hstore" of the xowiki/xowf
         # instances that want to use hstore to 1.
         #
-        # To update all hkey attributes in e.g. a package mounted at /xowf 
+        # To update all hkey attributes in e.g. a package mounted at /xowf
         # use:
         #
         #     ::xowf::Package initialize -url /xowf
         #     ::xowf::update_hstore $package_id
         #     ::xowiki::hstore::update_form_instance_item_index -package_id $package_id
         #
         # The first update command updates xowiki_page_instance, the second
-        # xowiki_form_instance_item_index. 
+        # xowiki_form_instance_item_index.
         #
         if {[::xo::dc has_hstore]} {
           ::xo::db::CrAttribute create hkey \
@@ -2057,7 +2057,7 @@
         return [:error_in_includelet $arg [_ xowiki.error-includelet-adp_syntax_invalid]]$ch2
       }
       set adp [string map {  " "} $adp]
-      
+
       #
       # Check the provided name of the adp file
       #
@@ -2067,7 +2067,7 @@
         incr ::xowiki_inclusion_depth -1
         return [:error_in_includelet $arg [dict get $path_info msg]]$ch2
       }
-      
+
       set adp_fn [dict get $path_info fn]
       #
       # check the provided arguments
@@ -4349,6 +4349,18 @@
     return [$page property $name $default]
   }
 
+  FormPage instproc lappend_property {name value} {
+    #
+    # lappend the specified value to the named property. If the
+    # property does not exists, create a new one.
+    #
+    if {[:exists_property $name]} {
+      :set_property $name [concat [:get_property -name $name] $value]
+    } else {
+      :set_property -new 1 $name $value
+    }
+  }
+
   FormPage instproc condition=is_true {query_context value} {
     #
     # This condition maybe called from the policy rules.